The Doctor (Doctor Who)

The Doctor was originally known as the Timeless Child, as revealed in "The Timeless Children" (2020). This episode substantially retconned the Doctor's history, as they had previously been said to be a high-born Time Lord whose incarnation played by William Hartnell in the show was born on Gallifrey. In the Doctor's revised and expanded origin story, a native Gallifreyan Shobogan scientist and explorer named Tecteun discovered the child as a young girl next to a portal to another reality. Tecteun adopted her as her own and discovered that the Child had a capacity to regenerate her body indefinitely. After much study, Tecteun genetically incorporated this ability into some of the Shobogan race, who became the basis for the formation of the elite Time Lords, although their regenerations were forcibly limited to twelve. After many regenerations, Tecteun inducted the Timeless Child into a clandestine operative group within the Time Lords known as the Division. The secrecy of the Division required Tecteun to eventually wipe all of the Timeless Child's memories up to that point and leave them, reduced in age to a child once again, in Gallifreyan society. This is where the Doctor's memories begin, with his boyhood as the First Doctor.[7]

The First Doctor's childhood on Gallifrey has been little described in the series. In "Hell Bent" the Doctor recalled his origins as a high-born Gallifreyan. In The Time Monster, the Doctor says he grew up in a house on a mountainside and talks about a hermit who lived under a tree behind the house and inspired the Doctor when he was depressed. He is later reunited with this former mentor, now on Earth posing as the abbot K'anpo Rimpoche, in Planet of the Spiders. In "The Girl in the Fireplace", according to Madame de Pompadour who psychically linked with the Doctor's memories, the Doctor experienced a very lonely childhood. An elderly woman on Gallifrey died and was shrouded in veils and surrounded by flies, giving the Doctor recurring nightmares, which the confession dial in "Heaven Sent" would later visualise to torment him. In "Listen", it is revealed the Doctor as a child often slept alone in a barn in the Drylands (a desert region outside the city capital), was withdrawn from other children, and was cared for by guardian figures who privately doubted the child's ability as an eventual Time Lord. Through the dialogue, it is suggested that several Gallifreyan children were pressured into joining the army, a path which did not sit right with the Doctor's pacifist beliefs, and as a result he wished to enroll into the Time Lord Academy instead.

The classic programme refers to his time at the Academy and his affiliation with the notoriously devious Prydonian chapter of Time Lords.[8] In "The Sound of Drums", the Doctor describes an Academy initiation where, at the age of 8, Gallifreyan children were taken from their families and made to look into the Untempered Schism, a gap in the fabric of reality, to view the Time Vortex. According to the Doctor, when regarding the effects of the initiation on participants: "Some would be inspired, some would run away and some would go mad (as he suggests happened to his nemesis, the Master)." When asked to which group he belonged, he replied, "Oh, the ones that ran away; I never stopped!". The Doctor was taught by future Lord President Borusa and Azmael,[9] where he met Drax, with whom he attended a Tech course as part of the class of '92.[9] In the Armageddon Factor, it is revealed that the Doctor scraped through the Academy with 51% on his second attempt.[10] In The Time Meddler, it is said that the Doctor was fifty years before the Meddling Monk.[9] In Time and the Rani, the Doctor claims to have attended university alongside the Rani, specialising in thermodynamics.[9]

At the academy, he met his childhood friend the Master and the pair grew up together. In "The End of Time", the Master recollects their childhood together where they would run all day across his father's field, described as 'pastures of red grass stretching far across the slopes of Mount Perdition' and the boys would call up at the sky. In "World Enough and Time", the Doctor claims that they both made a special pact where together they would visit every star in the universe; however, The Master was 'too busy burning them'. In "Hell Bent", one day at the Academy, the Doctor found himself lost inside the Cloisters (an area located deep beneath the citadel) and spent four days inside. He was contacted by a Wraith who told him about the prophecy of a legendary creature known as 'the Hybrid', prophesied to have been crossbred from two warrior races that would stand in the ruins of Gallifrey, unravel the Web of Time and burn a billion hearts to heal its own. The Wraiths then revealed to him the secret passage leading to another side of the city. The last anyone heard from him was that he apparently stole the moon and the President's wife; however, this was revealed to have been a lie spread about by the Shobogans when in reality it was the President's daughter and he lost the moon. This event had a massive impact on the Doctor, who theorized that he himself was possibly the Hybrid. The Doctor decided to leave Gallifrey out of fear.

The Doctor chose to steal a faulty Type 40 TARDIS in order to explore the universe. In "The Doctor's Wife" it is revealed that when the Doctor was young, he first saw the Tardis in a museum, where after stroking her console he commented that she was the most beautiful thing he had ever known. In "The Shakespeare Code", the Doctor once took a driving test to pilot the Tardis and failed. In Amy's Choice, the Doctor mentions that he threw the instruction manual in a supernova because he disagreed with it. In "The Name of the Doctor" the Tardis was later relocated in a repair shop which the Doctor managed to seize alongside his granddaughter Susan. In "The Doctor's Wife", Idris mentions that the Doctor had been travelling in the Tardis for 700 years, which indicates that he would have been 200 years old when he first borrowed her. In "Twice Upon a Time" it is revealed that the Doctor also left to investigate the mystery of why good prevails in a universe where evil would seem to have so many advantages. It would be after his encounter with his twelfth incarnation that the Doctor realized his actions made the difference in the balance between good and evil, stating "The universe generally fails to be a fairy tale, but that's where we come in."

In other media, more has been revealed of the Doctor's early life. In the Past Doctor Adventures novel Divided Loyalties, the Doctor recalls his Academy years in a dream induced by the Celestial Toymaker. According to this, he was a member of an organisation called the Deca, ten brilliant Academy students campaigning for increased Time Lord intervention, alongside Mortimus (the Meddling Monk), Ushas (the Rani), Koschei (the Master), Magnus (the War Chief), Drax, a spy named Vansell, Millennia, Rallon and Jelpax. With this group, he learns about the Celestial Toymaker and travels to his realm in a type 18 TARDIS with Deca members Rallon and Millennia, who are killed. This leads to the Doctor's expulsion from the Academy, condemned to five hundred years in Records and Traffic Control.[11] In The Quantum Archangel, it is revealed the Doctor studied cosmic science alongside the Master, taught by Cardinal Sendok.[12] In the Virgin Missing Adventures novel Goth Opera, it is said the Doctor was a frequent prankster while at the Academy, introducing cats into Gallifrey's ecosystem with his friend Ruath and electrifying a "perigosto stick" belonging to his teacher, Borusa.[9]

Feeling that too much of the Doctor's backstory had been revealed by the Seventh Doctor's era, writers Andrew Cartmel, Ben Aaronovitch and Marc Platt developed a new direction for the series. Cartmel wished to restore the character's "awe, mystery and strength" and make him "once again more than a mere chump of a Time Lord" – an idea the media dubbed the "Cartmel Masterplan".[13] Under Cartmel, the show foreshadowed this concept; however, its 1989 cancellation meant that it was never realised onscreen. The proposed backstory was fully explored in Platt's 1997 novel Lungbarrow, where the Doctor is revealed as "the Other", a mysterious figure in Gallifreyan lore who co-founded Time Lord society with Rassilon and Omega. After a curse renders Gallifrey sterile, the Other devises biotechnological looms to "weave" new Time Lords; his granddaughter Susan is Gallifrey's last natural child. To escape a civil war with Rassilon, the Other throws himself into the loom system, where he is disintegrated and later woven into the Doctor.[13][14]

References to the Doctor's family are rare in the programme. During the first two seasons, he travelled with his granddaughter, Susan Foreman, who has since been referred to occasionally and who returned in The Five Doctors. In "The Tomb of the Cybermen" when asked about his family, the Second Doctor says his memories of them are alive when he wants them to be otherwise they sleep in his mind and he forgets. In The Curse of Fenric, when asked if he has family, the Seventh Doctor replies that he does not know. In the 1996 television movie, the Eighth Doctor remarks that he is half-human on his mother's side, and recalls watching a meteor storm with his father on Gallifrey. The revived series never addresses a human mother again and at times even contradicted this remark: The half-human clone of the Tenth Doctor is initially disgusted to be half-human ("Journey's End") and the Twelfth Doctor rejects that he could be a hybrid of human and Time Lord ("Hell Bent"). Furthermore, an unnamed Time Lady appearing throughout The End Of Time which the Tenth Doctor appears to recognize towards the end of the story was intended to be the Doctor's mother.[15] The Doctor mentions having had a brother in "Smith and Jones", and sisters in "Arachnids in the UK". In "It Takes You Away", the Doctor claims that she had seven grandmothers. Later in the same scene, she mentions that her favourite grandmother, Granny 5, alleged Granny 2 was "a secret agent for the Zygons".[16]

Throughout the revival, the Doctor routinely attempts to change the topic when questioned about being a parent or his family life, as in "Fear Her", "The Beast Below" and "A Good Man Goes to War". In "The Empty Child", a hospital doctor named Dr. Constantine says to him, "Before this war began,[note 1] I was a father and a grandfather. Now I'm neither. But I'm still a doctor." The Ninth Doctor's reply is, "Yeah. I know the feeling." In "The Doctor's Daughter", when discussing the topic of parenthood, the Tenth Doctor confirms that he had at one point been a father and that he lost his children 'a long time ago', saying 'When they died that part of me died with them'; the nature of their deaths, however, has never been explained, as it is suggested that whatever happened to his family is very painful for the Doctor to talk about. In "The Woman Who Fell to Earth" when the Thirteenth Doctor is questioned how she copes with the loss of her family, she states that she carries the memories of them with her and thus makes them a part of who she is, saying "even though they're gone from the world ... they're never gone from me."

In "The End of Time", a mysterious individual, referred to only in the credits as "The Woman", appears unexpectedly to Wilfred Mott throughout both episodes. She is later revealed to be a dissident Time Lady, who opposed the Time Lord High Council's plan to escape the Time War. When she reveals her face to the Doctor, his reaction indicates that he recognises her. Julie Gardner, in the episode's commentary, states that while some have speculated that the Time Lady is the Doctor's mother, neither she nor Russell T. Davies is willing to comment on her identity. When later asked by Wilfred who she was, the Doctor evades answering the question, making their connection unclear. In Doctor Who: The Writer's Tale – The Final Chapter, Russell T Davies states that he created the character to be the Doctor's mother and this is what actress Claire Bloom was told when she was cast.

In spin-off media, several individuals related to the Doctor have made appearances, and do not appear in the television series, such as his grandchildren John and Gillian, who appeared alongside the First and Second Doctors in comics and annuals. Two different, conflicting accounts exist on the descendants of Susan after leaving the Doctor. In the audio play "An Earthly Child", it is revealed that Susan has had a half-human child, Alex Campbell, the Doctor's great-grandson. Alternatively, in the novel Legacy of the Daleks, Susan and her husband David adopt three children whom they name David Campbell Jr, Ian and Barbara; named after David himself, Ian Chesterton and Barbara Wright, respectively. Irving Braxiatel, a character first introduced in the novel Theatre of War, was initially hinted at, and later confirmed to be, the Doctor's biological older brother. He has since become a recurring character, especially within the Big Finish spin-off audio series Gallifrey and Bernice Summerfield.

In the novel Father Time, the Eighth Doctor, during his hundred-year exile on Earth, found an orphaned Time Lord girl named Miranda whom he adopted and raised until she was 16. In the novel Sometime Never..., she returned to the Doctor with her daughter Zezanne. She was also the central character in a three-issue comic book series published by Comeuppance Comics in 2003. Author Lance Parkin, who devised the character of Miranda, has hinted that her real father is a future incarnation of the Doctor which, if so, would make Zezanne the Doctor's biological granddaughter as well. The Virgin New Adventures novel Lungbarrow presents an alternative take on the Doctor's origins, suggesting that Time Lords are "loomed" in large batches of "cousins" and not produced via sexual reproduction. Lungbarrow portrays the Doctor as one of 45 cousins grown from his house's genetic loom as an adult. By contrast, the TV programme has shown Time Lords as children and stated that Time Lords can have sexual relationships.

The Doctor is assumed to be or to have been married to Susan's grandmother, including by head writer Steven Moffat. In "Blink", the Doctor mentioned that he was rubbish at his own wedding. In The Virgin New Adventures novel Cold Fusion, a Time Lord lady named Patience who was the widow of Omega, one of the founding-fathers of Gallifreyan society who fell into an anti-matter universe. Patience later met and married the Doctor and together they had thirteen children. Once their first-born son announced the arrival of a baby, the family was targeted by the Lord President, as the child was to be conceived naturally and only the Loom-born could inherit the Legacy of Rassilon; as a result, the Doctor's children were systemically culled. The Doctor managed to help Patience escape through the use of the Machine, a prototype TARDIS, after assuring that her daughter-in-law had given birth to a girl named Susan and promised that he would keep the child safely away from Gallifrey.

In "The Wedding of River Song", he marries a recurring companion and love interest River Song. Comments by both River and the Doctor in the seventh series, particularly in "The Angels Take Manhattan", confirmed that they were married; in "The Name of the Doctor", the Doctor refers to her as his "wife" after seeing a grave stone with her name on it, after initially answering "yes" when Clara asks if she was an "ex".

In "The End of Time", the Tenth Doctor mentions marrying Queen Elizabeth I and implies that they had sex, stating: "her nickname [the Virgin Queen] is no longer...". The joke continues in "The Beast Below", featuring future British monarch Queen Elizabeth X or Liz Ten, and the marriage is finally shown in "The Day of the Doctor" during an adventure with Zygons. In the 2010 Christmas special, "A Christmas Carol", the Eleventh Doctor accidentally marries Marilyn Monroe but later questions the authenticity of the chapel in which they were married. Steven Moffat did not consider the marriages to Elizabeth I and Marilyn Monroe to count when questioned on how many wives the Doctor had had, remarking that he was married to Susan's grandmother and River Song.

An adventurous scientist, the Doctor usually solves problems with his wits rather than with force. With the exception of his sonic screwdriver, the Doctor detests weapons and uses violence only as a last resort.[17] According to the alien villain Chedaki in the episode The Android Invasion, "his entire history is one of opposition to conquest."

As a time traveller, the Doctor has been present at, or directly involved in, countless major historical events on the planet Earth and elsewhere – sometimes more than once. In the 2005 series premiere, "Rose", it is revealed that the Ninth Doctor was instrumental in preventing a family from boarding the Titanic prior to her fateful voyage. In "The End of the World", the Doctor recalls having been on board and surviving the Titanic's sinking to find himself "clinging to an iceberg". The Fourth Doctor mentioned this event in Robot and The Invasion of Time, where he insists that the sinking was not his fault; the Seventh Doctor became involved in the sinking when tracking an alien entity in the novel The Left-Handed Hummingbird. The Doctor has also encountered many of Earth's historical figures.

It is his tendency for becoming "involved" with the universe – in direct violation of official Time Lord policy – that has caused the Doctor to be labelled a renegade by the Time Lords as stated in The War Games. However, the Doctor's actions are largely tolerated as he saved Gallifrey and the universe several times. The Time Lords are partial to sending him on missions when deniability or expendability is needed, implied to have begun after his capture during The War Games and witnessed further in later stories, the Time Lords directing the Doctor and/or the TARDIS to specific locations in Colony in Space, The Curse of Peladon, The Mutants, Genesis of the Daleks, The Brain of Morbius and Attack of the Cybermen. The Doctor's standing in Time Lord society has waxed and waned over the years, from being a hunted man who was eventually punished with a forced regeneration and an exile sentence on Earth, to being appointed Lord President of the High Council. He does not assume the office for very long, fleeing Gallifrey after his appointment rather than accepting the limitations on his freedom that the role would place on him (The Five Doctors), and is eventually deposed in absentia (The Trial of a Time Lord). By the time of his twelfth incarnation, he is regarded by many Gallifreyans as a war hero, "the man who won the Time War" ("Hell Bent").

In the first series of the 2005 revival, writer Russell T Davies introduced the concept of the Time War to streamline the Doctor's backstory for new viewers of the show. It was a war across all of time and space which ended when the Doctor presumably destroyed both the Time Lords and the Daleks. The Doctor's remorse for his actions in his Ninth, Tenth and Eleventh incarnations is a key part of his characterisation throughout the revival. The Time War happened between the 1996 television movie and 2005 opening episode "Rose" according to the show's internal chronology, although the events of past serials such as Genesis of the Daleks have been retroactively attributed to the Time War.[18] It was never shown on-screen until "The End of Time", which was both Davies' last story as head writer and producer and David Tennant's last regular story as the Tenth Doctor. This episode featured brief views of Gallifrey and the Time Lords on the last day of the Time War.

The 2013 mini-episode "The Night of the Doctor", released as a prelude to the 50th anniversary special, featured Paul McGann reprising his role as the Eighth Doctor and was set during the Last Great Time War, albeit much earlier than during "The End of Time". The mini-episode presented him as a conscientious objector to the war who regenerated under controlled circumstances into the War Doctor (John Hurt), a previously unseen incarnation created retroactively by Davies' successor as head writer, Steven Moffat, for the 50th anniversary special "The Day of the Doctor". The Tenth and Eleventh Doctors explained that Hurt's regeneration was not the Doctor because his actions during the Time War were a betrayal of the promise that name symbolized. "The Day of the Doctor" revisited the last day of the Time War after "The End of Time "and revealed that the interference of the future Doctors and future companion Clara Oswald caused the War Doctor to change his plan at the last moment. Ultimately, Gallifrey was hidden in a parallel dimension and the Daleks destroyed themselves in the ensuing crossfire; to all observers, it appeared as though the two races had been annihilated together. The unsynchronized timestreams caused the War Doctor to forget the specifics of his actions at this time. The Doctor remembered committing the apparent genocide during the lives of his ninth, tenth and eleventh incarnations up until the time of the Eleventh Doctor's present.

Quite apart from his name, why the Doctor uses the title "The Doctor" has never been fully explained on screen. The Doctor, at first, said that he was not a physician, often referring to himself as a scientist or an engineer.[40] However, he does occasionally show medical knowledge and has stated on separate occasions that he studied under Joseph Lister and Joseph Bell. In The Moonbase (1967), the Second Doctor mentions that he studied for a medical degree in Glasgow during the 19th century. The Fourth Doctor was awarded an honorary degree from St. Cedd's College, Cambridge in 1960.[note 5] He has been mocked by his fellow Time Lords for adhering to such a "lowly" title as "Doctor", although in The Armageddon Factor (1979), Drax congratulates him on achieving his doctorate, indicating it was at least a somewhat respectable title. In "The Girl in the Fireplace" (2006), he draws an analogy between the title and Madame de Pompadour's.

In The Mutants (1972) an official asks the Third Doctor if he is, in fact, a doctor, to which the Doctor replies "I am, yes"; when asked what he is qualified in, the Doctor replies, "Practically everything." The Fourth Doctor states that his companion, Harry Sullivan, is a Doctor of medicine, while he is "a doctor of many things" (Revenge of the Cybermen, 1975). The Fifth Doctor claims to be a doctor "of everything" in Four to Doomsday (1982), and a message to the same effect is related from the Tenth Doctor in "Utopia" (2007). In talking with Harry in Robot (1974–1975) the Doctor states "You may be a doctor, but I'm the Doctor. The definite article, you might say." In The Ark in Space (1975), aired later that year, the Doctor states that his doctorate is only honorary; the Tenth Doctor, however, considers the name to be his legitimate academic rank in "The Waters of Mars" (2009), describing his "name, rank and intention" as "The Doctor; doctor; fun." In an interview with The Age in 2003, Tom Baker mentioned that the Doctor is called so because he is "a doctor of time and relative dimension in space".[41] Apart from being called a doctor of the TARDIS, the Doctor has been referred to as a "doctor of time travel."[42]

The revived programme establishes that Time Lords invent their own names. In "The Sound of Drums" (2007), the Tenth Doctor remarks to the Master that they both chose their names, with the Master calling him sanctimonious for identifying himself as "the man who makes people better." The Eleventh Doctor, in "The Name of the Doctor", and repeated in the next episode, "The Day of the Doctor", by the War Doctor, Tenth Doctor and Eleventh Doctor (collectively), elaborate that the name is a promise to be: "Never cruel or cowardly. Never giving up and never giving in." By contrast, the Eleventh Doctor had earlier spoke of the War Doctor as being the man who broke that promise, being the one to fight in the Time War before learning the actual fate of the Time Lords. Since contradicted by the television series, the 2003 Telos novella Frayed by Tara Samms, set prior to the programme's first episode in 1963, presents the alternative explanation that the Doctor was given that name by medical staff on a foreign planet and liked it.

To make up for his lack of a practical name, the Doctor often relies upon convenient pseudonyms. In The Gunfighters (1966), the First Doctor uses the alias Dr. Caligari. In The Highlanders (1966–67), the Second Doctor assumes the name of "Doctor von Wer" (a German approximation of "Doctor Who"), and signs himself as "Dr. W" in The Underwater Menace. He similarly poses as "the Great Wizard Quiquaequod" in The Dæmons (qui, quae and quod being, respectively, the masculine, feminine and neuter Latin translation of the nominative form of who). The Master was utilising Latin translation in the same serial, posing as "Mr Magister". The Eighth Doctor's companion Grace briefly refers to him by the alias "Dr. Bowman" in the 1996 Doctor Who television movie.[43]

In The Wheel in Space (1968), his companion Jamie McCrimmon, reading the name on medical equipment, tells the crew of the Wheel that the Doctor's name is "John Smith". The Doctor subsequently adopts this alias numerous times over the course of the programme, sometimes prefixing the title "Doctor" to it.

In the audio adventure, The Sirens of Time, when the Fifth Doctor is asked his name, this conversation ensues:

"I'm the Doctor."
"Doctor? That's a profession, not a name."
"It's all I have."

To his greatest enemies, the Daleks, the Doctor is known as the Ka Faraq Gatri, the "Enemy of the Daleks", the "Bringer of Darkness" or "Destroyer of Worlds". This is first mentioned in the novelisation of Remembrance of the Daleks by Ben Aaronovitch and subsequently taken up in the spin-off media, particularly the Virgin New Adventures books and the Doctor Who Magazine comic strip. Davros uses the title "Destroyer of Worlds" to describe the Doctor in "Journey's End" (2008). In the Virgin New Adventures novel Love and War, the Doctor is referred to as "The Oncoming Storm" by the Draconians (whose word for it is "Karshtakavaar"); according to the episode "The Parting of the Ways" (2005), the same title is used by the Daleks. The Doctor refers to himself as "The Oncoming Storm" in "The Lodger" (2010). In "Asylum of the Daleks" (2012), it is stated that Daleks refer to the Doctor as "The Predator". The Virgin New Adventure Zamper establishes that the Chelonians refer to him as "Interfering Idiot".

The Doctor's calling card (from Remembrance of the Daleks)

The programme has occasionally toyed with the Doctor's identity (or lack thereof). In the first part of The Mysterious Planet (1986), the Doctor suggests writing a thesis on "Ancient Life on Ravolox, by Doctor...", but is interrupted by his companion Peri. In The Armageddon Factor, the Time Lord Drax addresses the Fourth Doctor as "Thete", short for "Theta Sigma". Later, in The Happiness Patrol (1988), this was clarified as a nickname from the Doctor's university days; he is called by this name again in the Paul Cornell novel Goth Opera. In Remembrance of the Daleks, the Seventh Doctor produces a calling card with a series of pseudo-Greek letters inscribed on it (as well as a stylised question mark). This may be a reference to The Making of Doctor Who (1972), by Terrance Dicks and Malcolm Hulke, which claims that the Doctor's true name is a string of Greek letters and mathematical symbols.

The question mark motif was common throughout the 1980s, in part as a branding attempt. Beginning with season eighteen, the Fourth through Seventh Doctors all sported costumes with a red question mark motif (usually on the shirt collars, except for the Seventh Doctor – it appeared on his pullover and in the shape of his umbrella handle). In the 1978 serial The Invasion of Time, the Fourth Doctor is asked to sign a document; although the signature itself is not directly seen on screen, his hand movements clearly indicate that he signs it with a question mark. A similar scene occurs with the Seventh Doctor in Remembrance of the Daleks.

In the early years of the franchise, the character was credited as "Doctor Who" or "Dr Who", up to the final story of season 18, Logopolis (1981), which was the last story featuring Tom Baker as the then-incumbent Fourth Doctor. Beginning with the debut of Peter Davison as the Fifth Doctor in Castrovalva (1982), the character was credited as "The Doctor", which he had been referred to in-universe since the tenure of William Hartnell. This credit remained from season 19 to season 26. In the television movie, the trend is continued, with Paul McGann's debuting Eighth Doctor credited as "The Doctor" and Sylvester McCoy's out-going Seventh Doctor as "The Old Doctor". The 2005 resurrection of the programme credited Christopher Eccleston – playing the Ninth Doctor – as "Doctor Who" again in series 1. "The Parting of the Ways", featuring the Ninth Doctor's regeneration into the Tenth Doctor (David Tennant) credits Tennant as "Doctor Who". The credit reverted to "The Doctor" for 2005's Christmas special "The Christmas Invasion" and all subsequent stories at Tennant's request.[44] Matt Smith, Peter Capaldi and Jodie Whittaker have continued to be credited as "The Doctor".

John Hurt plays a mysterious past incarnation of the Doctor in the 50th anniversary special "The Day of the Doctor", with minor roles in "The Name of the Doctor" and mini-episode "The Night of the Doctor", created as a "mayfly Doctor" by Steven Moffat. In the television episodes, he is credited as "The Doctor", but he is introduced as "The War Doctor" in "The Night of the Doctor".[45] The end of "The Name of the Doctor" closes with text superimposed over footage of Hurt introducing him, pictured to the left, which was unprecedented for the show. In "The Day of the Doctor", Hurt appears in a "multi-Doctor" special alongside Matt Smith and David Tennant as the Eleventh and Tenth Doctors, respectively. The three are collectively credited as "The Doctor" alongside Christopher Eccleston, Paul McGann, Sylvester McCoy, Colin Baker, Peter Davison, Tom Baker, Jon Pertwee, Patrick Troughton and William Hartnell, although the latter nine appeared only through the reuse of archive footage. Tom Baker did reappear, but as "the Curator", an ambiguously different character who he was not credited for playing. A voice actor, John Guilor, recorded a line of audio impersonating the First Doctor, for which he was credited as "Voice Over Artist".

In other multi-Doctor stories, the multiple actors are all credited as "The Doctor", the exception being The Three Doctors (1972–73), which credited William Hartnell, Patrick Troughton and Jon Pertwee as "Doctor Who" as the 1972 serial preceded the practice of crediting the character as "The Doctor". In "Human Nature" (2007), the plot involves the Tenth Doctor altering his biology and becoming a human to avoid detection. As a human, he takes the name "John Smith". David Tennant is credited as "The Doctor/Smith" for the episode, although the two-parter's concluding episode, "The Family of Blood" (2007), credits him simply as "The Doctor".

The actors who have played the lead role of the Doctor in the programme and the dates of their first and last regular television appearances in the role, are:

In addition to the above-listed actors, others have played versions of the Doctor for the duration of particular storylines. Notably, John Hurt guest starred as the War Doctor in the closing moments of the 2013 episode "The Name of the Doctor", the webcast "The Night of the Doctor" and the 50th Anniversary episode "The Day of the Doctor". The War Doctor is an incarnation existing between those of McGann and Eccleston.[47] Hurt was never the programme's lead actor; his Doctor was retroactively inserted into continuity for the programme's 50th anniversary, and was written so as not to disturb the ordinal naming of the established Ninth, Tenth and Eleventh Doctors.[48] In the 1986 serial The Trial of a Time Lord, Michael Jayston played the Valeyard, an amalgamation of the Doctor's darker sides from between his twelfth and final incarnations. In the Series 12 episode "Fugitive of the Judoon", Jo Martin played a previous and unknown incarnation of the Doctor who existed at some point before the Time War.[49] The capacity for the Doctor to have other previously-unknown regenerations prior to the First Doctor was introduced in "The Timeless Children" (2020),[7] having previously been hinted at in the serial The Brain of Morbius.[50]

While the Doctor remains essentially the same person throughout their regenerations, each actor has purposely imbued the character with distinct quirks and characteristics, and the production teams dictate new personality traits for each actor to portray.

Several personality traits remain constant throughout the Doctor's incarnations,[1] most notably a disarming or mercurial surface, concealing a deep well of age, wisdom, melancholy, and darkness. This duality is explored more overtly in the revived series (2005–present), which has described him as "fire and ice and rage, he's like the night and the storm in the heart of the sun, he's ancient and forever, he burns at the centre of time..."[51] and "the man who can turn an army around at the mention of his name".[52] Though the Doctor tends to present a jocular, even childlike, persona, when the stakes rise—e.g., in Pyramids of Mars (1975)—that mask tends to fall, revealing a Doctor who is cold, driven, at times callous.

This dark side sits in contrast to the Doctor's deep compassion, which manifests to different strength and effect across their incarnations. The Doctor prefers a pacifist solution to most problems, and is an ardent champion of life and dignity over violence and war.[53] Their pacifism runs deeply enough to, on many occasions, doubt the morality of destroying their worst enemies - the Daleks. Their compassion for their fallen friend, the Master, often runs against clear reason or self-interest, as when they urge a dying Master to regenerate ("Last of the Time Lords") or vows to watch over them for 1,000 years in order to avert their execution ("Extremis").

The Doctor has a deep sense of right and wrong, and a conviction that it is right to intervene when injustice occurs, which sets them apart from their own people, the Time Lords, and their strict ethic of non-intervention.

Often the Doctor is critical of others who employ deadly force, be they their companions (Leela in The Face of Evil and The Talons of Weng-Chiang (1977); Jack Harkness in "Utopia" (2007)) or other supporting characters. In the episode "The Lodger" (2010), a member of the Doctor's football team offhandedly mentions annihilating the team they will play next week. The Doctor looks very angry and says, "No violence, not while I'm around, not today, not ever. I'm the Doctor, the oncoming storm... and you basically meant beat them in a football match, didn't you?"

The Doctor has a particular dislike for ranged weapons such as firearms or rayguns and tends to make a special effort to avoid their use. The Tenth Doctor especially makes a show of his distaste, discarding guns while declaring "I never would!" ("The Doctor's Daughter") and asserting that he is unarmed: "That's me. Always." ("Doomsday"). On some rare occasions, the Doctor does make use of weapons (as in Day of the Daleks, The Talons of Weng Chiang, and Resurrection of the Daleks), but most of the time it is usually to bluff or employ for an alternative use, e.g., destroying a machine vital to their enemies' scheme ("The End of Time").

Nonetheless, when brought to an extreme (e.g., Earthshock, Vengeance on Varos, "The Christmas Invasion") the Doctor may resort to violence—even deadly force—to protect those considered under the Doctor's care. In Remembrance of the Daleks (1988), the Doctor even contrives for the Daleks' homeworld, Skaro, to be destroyed, albeit manipulating the Daleks into doing it themselves after he sabotaged their equipment. Starting with the 2005 revival, the Doctor carries the weight of a Time War between the Daleks and his people, the Time Lords, in which he believes himself responsible for the genocide of both races, in aid of the greater good, but this burden was lessened after "The Day of the Doctor" revealed that the Doctor's thirteen incarnations joined forces to save Gallifrey and create the illusion of its destruction.

Bearing the strain of his wartime actions, the Ninth Doctor deliberately tortures a lone Dalek he encounters ("Dalek"), despite its pleas to "have pity," stating coldly, "you never did." The Tenth Doctor notably declares a "one chance only" policy when dealing with aliens invading the Earth, leading his companion Donna Noble to comment that he needs "someone" to keep his temperament in check. In "The Family of Blood" (2007), a defeated alien reflects that the Doctor "never raised his voice – that was the worst thing, the fury of a Time Lord". Through the course of his adventures, the Eleventh Doctor underwent significant personality shifts, becoming ever more ruthless when travelling alone; falling into a deep depression and inertia when his friends Amy and Rory were lost to him, and finally undergoing a manic change at the prospect that Clara Oswin Oswald was still alive. By contrast, the Twelfth Doctor became a lighter person over the course of his life, beginning with a grim mood where he may have dropped a man out of a hot air balloon and questioning his own nature ("Into the Dalek") but ending with a firm resolve that he would take the hard option just because it was right ("The Doctor Falls").

Different actors have used different regional accents in the role. The first six Doctors spoke in Received Pronunciation or "BBC English", as was standard on British television at the time. Sylvester McCoy used a very mild version of his own Scottish accent in the role, and Paul McGann spoke with a faint Liverpudlian lilt. Only rarely is this even addressed in the programme. In the case of McGann's Doctor, who is identified by American characters as "British", he seems only slightly conscious of the way he sounds, responding with "Yes, I suppose I am." When the accent of Eccleston's Doctor is clearly described as "Northern", he responds with the line "Lots of planets have a North." Capaldi's portrayal of the Doctor explicitly identified his own accent as "Scottish" after commenting on the English accents of his friends, Jenny Flint and Clara Oswald,[54] while experiencing post-regeneration amnesia ("Deep Breath"). Whittaker's Thirteenth Doctor speaks with the actress' natural Yorkshire accent and is identified as British during a trip to America.

Another example is in The Tomb of the Cybermen when the Doctor is identified as "English" and, dissembling, plays along. Though David Tennant speaks with a natural Scottish accent, he played the Tenth Doctor with an Estuary accent (apart from when, in the Highlands-set episode "Tooth and Claw", the character is pretending to be a local). According to producer Russell T Davies, this was intended as a consequence of spending so much time with Rose. "The Christmas Invasion" would have alluded to this, but the line was cut. Davies also said that after Eccleston's accent, he did not want Tennant "touring the regions" with a Scottish one,[note 7] and so asked Tennant to affect the same accent he used for the earlier BBC period drama Casanova.[55] In contrast, Peter Capaldi was explicitly allowed to continue using his native Scottish accent as the Twelfth Doctor.[56]

In the Big Finish audio adventure The Sirens of Time, the captain aboard a German U-boat assumes that he is English because of the way he pronounces his words: "So, you speak German ... but you speak it like an English gentleman."

The Doctor's clothing has been equally distinctive, from the distinguished Edwardian suits of the First Doctor to the Second Doctor's rumpled, clown-like Chaplinesque attire to the dandyish frills and velvet of the Third Doctor's era. The Fourth Doctor's long frock coat, loose-fitting trousers, occasionally worn a wide-brimmed hat and trailing, multi-striped scarf added to his somewhat shambolic and bohemian image; the Fifth's Edwardian cricketer's outfit suited his youthful, aristocratic air as well as his love of the sport (with a stick of celery on the lapel for an eccentric touch, though in The Caves of Androzani (1984), it is revealed to turn purple when exposed to gases the Doctor is allergic to); and the Sixth's multicoloured jacket, with its cat-shaped lapel pins, reflected the excesses of 1980s fashion. The Seventh Doctor's outfit – a Panama hat, a coat with a scarve, a tie, checked trousers and brogues/wing-tips – was more subdued and suggestive of a showman, reflecting his whimsical approach to life. In later seasons, as his personality grew more mysterious, his jacket, tie and hatband all grew darker.

Throughout the 1980s, question marks formed a constant motif, usually on the shirt collars or, in the case of the Seventh Doctor, on his sleeveless jumper and the handle to his umbrella.[57] The idea was grounded in branding considerations, as was the movement starting in Tom Baker's final season toward an unchanging costume for each Doctor, rather than the variants on a theme employed over the first seventeen years of the programme. When the Eighth Doctor regenerated, he clad himself in a 19th-century frock coat and shirt based on a Wild Bill Hickok costume, reminiscent of the out-of-time quality of earlier Doctors and emphasising the Eighth Doctor's more Romantic persona.

In contrast to the more flamboyant outfits of his predecessors, the Ninth Doctor wore a nondescript, weathered black leather jacket, V-neck jumper and dark trousers. Eccleston stated that he felt that such definitive "costumes" were passé and that the character's trademark eccentricities should show through his actions and clever dialogue, not through gimmicky costumes. Despite this, there is a running joke about his character that the only piece of clothing he changes is his jumper, even when trying to "blend into" a historical era. The one exception, a photograph of him taken in 1912, wearing period gentleman's clothing, resembles the style of the Eighth Doctor.

The Tenth Doctor sports either a brown or a blue pinstripe suit – usually worn with ties – a tan ankle-length coat and trainers, the latter recalling the plimsolls worn by his fifth incarnation. Also like that incarnation (and his first one), he occasionally wears spectacles. In the 2007 Children in Need "Time Crash" special he states that he does not actually need glasses to see, but rather wears them to "look a bit clever", as did the Fifth, whom he meets in the special. On occasions, he wears a black tuxedo with matching black trainers. In interviews, Tennant has referred to his Doctor's attire as geek chic. According to Tennant, he had always wanted to wear the trainers. The overall costume was influenced by an outfit worn by Jamie Oliver in a TV interview on the talk show Parkinson.[58]

The Tenth Doctor says in "The Runaway Bride" that, like the TARDIS, his pockets are bigger on the inside. The Second, Fourth, Sixth, Seventh, Eleventh and Twelfth Doctors routinely carried numerous items in their coats without this being conspicuous.

The Eleventh Doctor's appearance has been described as appearing like "an Oxford professor", with a tweed jacket, red or blue striped shirt, red or blue bow tie, black or grey trousers with red or blue braces, and black boots.[59] He maintains "Bow ties are cool" even when his companions do not agree, and is delighted to meet Dr Black, the first man who agrees with him, in the episode "Vincent and the Doctor" (2010). As a running gag, he exhibits attraction to unusual hats, like a fez, a pirate hat and a stetson, often only to have them destroyed by River Song shortly afterwards. Starting in the second half of series 7, the Eleventh Doctor reverted to wearing a frock coat, similar to those worn by his predecessors, with a waistcoat and black trousers, black braces, an off-white shirt, bow tie and brown boots. He also added round-rimmed glasses that belonged to former companion Amy Pond.

The Twelfth Doctor's costume has been described as looking like a magician.[60] It echoes his third incarnation's look, specifically the red lining on the inside of his Crombie coat. It has been described as "no frills, no scarves, just 100% rebel Time Lord."[61] The Twelfth Doctor wears a white shirt with no tie, with his top button fastened and no cuff links, a dark blue cardigan (sometimes replaced with a waistcoat), navy trousers and black boots.

The Thirteenth Doctor's costume features blue high-waisted culottes with yellow braces, a navy blue or burgundy shirt with a rainbow stripe across it, a lilac-blue coat, brown lace-up boots, blue socks and piercings on her left ear. During the clip where Whittaker was announced as the new Doctor, she wore a grey overcoat over a black hoodie, reminiscent of Capaldi's costume.

The Doctor has occasionally expressed distaste and confusion about his own fashion choices in other incarnations. The First Doctor referred to his third incarnation as a "Dandy", and his second incarnation as a clown.[lower-alpha 1] The Tenth Doctor cringed at his fifth self's choice of wearing celery on his lapel.[lower-alpha 2] The Eleventh Doctor, upon meeting his previous self, referred to his Converse trainers as "sand-shoes."[lower-alpha 3] The Twelfth Doctor believes his previous incarnation's long scarf "looked stupid"[lower-alpha 4] and his prior's love of bow-ties is "embarrassing."[60]

Each regeneration to date has been worked into the continuing story, and most regenerations (minus the Second-to-Third) have been portrayed on-screen, in a handing over of the role. Before permanently dying, a Time Lord can regenerate twelve times for a total of thirteen incarnations.[62] The following list details the manner of each transition between incarnations:

• First Doctor (William Hartnell): Steadily weakening from the Cybermen's attempt to drain all of Earth's energy before being "renewed" by the TARDIS in The Tenth Planet (1966). Briefly stalled in "Twice Upon a Time" (2017).
• Second Doctor (Patrick Troughton): A forced "change in appearance" and exile to Earth by the Time Lords in the closing moments of The War Games (1969).
• Third Doctor (Jon Pertwee): Radiation poisoning from the Great One's cave of crystals on the planet Metabilis 3 at the end of Planet of the Spiders (1974).
• Fourth Doctor (Tom Baker): Fell from the Pharos Project telescope and merged with a mysterious "in-between" incarnation named 'The Watcher' in Logopolis (1981)
• Fifth Doctor (Peter Davison): Succumbed to spectrox poisoning, contracted near the start of The Caves of Androzani (1984).
• Sixth Doctor (Colin Baker): Severely injured when the Rani crash-landed the TARDIS on the planet Lakertya at the start of Time and the Rani (1987).[note 8]
• Seventh Doctor (Sylvester McCoy): Gunned down during a San Francisco gang shooting in the 1996 television movie, and died during exploratory heart surgery by a doctor unfamiliar with Time Lord physiology.
• Eighth Doctor (Paul McGann): Died from crash-landing a gunship on the planet Karn in "The Night of the Doctor" (2013). There, the Sisterhood of Karn revived the Doctor and provided an elixir that allowed him to choose the outcome of his next regeneration.
• War Doctor (John Hurt): Having spent the duration of this incarnation's lifetime fighting in the Time War, regenerates due to "wearing a bit thin" in "The Day of the Doctor" (2013).
• Ninth Doctor (Christopher Eccleston): Cellular degeneration caused by absorbing the energies of the time vortex from Rose Tyler in "The Parting of the Ways" (2005).
• Tenth Doctor (David Tennant): Having aborted one regeneration to heal from Dalek gunfire in "Journey's End" (2008), he later succumbs to radiation poisoning incurred while saving Wilfred Mott, using up his twelfth regeneration in "The End of Time" (2009–10).
• Eleventh Doctor (Matt Smith): Aged after several hundred years defending the planet Trenzalore, and in his final body, the Time Lords grant the Doctor a new regeneration cycle in "The Time of the Doctor" (2013).
• Twelfth Doctor (Peter Capaldi): Electrocuted by a Cyberman aboard a colony ship in "The Doctor Falls" (2017). Initially refusing to change again, the Doctor finally embraces regeneration at the end of "Twice Upon a Time" (2017).
• Thirteenth Doctor (Jodie Whittaker): Fatally wounded by The Master who directed a beam of energy, that was designed to destroy a planet, at the Doctor in "The Power of the Doctor" (2022).

The Doctor's first (Hartnell to Troughton), ninth (Hurt to Eccleston), and thirteenth (Smith to Capaldi) regenerations occur due to natural causes – in all three cases, the Doctor shows increasing signs of age, and comments that his body is "wearing a bit thin," though in the First Doctor's case this is apparently exacerbated by the energy drain from Mondas. All of the other regenerations have been caused by external factors, such as radiation poisoning, infection or fatal injuries.

In the original programme, with the exception of the change from Troughton to Pertwee, regeneration usually occurred when the previous Doctor was near "death". The changeover from McCoy to McGann was handled differently, with the Doctor actually dying and being dead for a time before regeneration occurred. The Eighth Doctor comments at one point in the television movie that the anaesthesia interfered with the regenerative process and that he had been "dead too long", accounting for his initial amnesia. Kate Orman's novel The Room with No Doors, set just before the regeneration, notes that this is one of the few regenerations in which the Doctor was not conscious and aware that he was dying.

The Second Doctor (Troughton), was the only Doctor whose regeneration was due to nothing more than a need to change his appearance. He was not aged, in ill health nor mortally wounded at the end of The War Games (1969). Prior to his exile, the Time Lords deemed that his current appearance was too well known on Earth and therefore forced a "change of appearance" on him. This method of changing appearance was a source of early speculation that the Second and Third Doctor were actually the same incarnation since the second was never seen to truly "die" onscreen. Continuity has since established that one of his allotted regenerations was indeed used up for this transition.

The 2005 series began with the Ninth Doctor already regenerated and fully stabilised, with no explanation given. In his first appearance in "Rose" (2005), the Doctor looked in a mirror and commented on the size of his ears, suggesting that the regeneration may have happened shortly prior to the episode, or that he has not examined his reflection recently. Russell T Davies, writer/producer of the new series, stated in Doctor Who Magazine that he had no intention of showing the regeneration in the series, and that he believed the story of how the Eighth Doctor became the Ninth is best told in other media. In Doctor Who Confidential, Davies revealed his reasoning that, after such a long hiatus, a regeneration in the first episode would not just be confusing for new viewers but lack dramatic impact, as there would be no emotional investment in the character before he was replaced. The circumstances of the Eighth Doctor's regeneration were explored during the 2013 specials, with the revelation of the incarnation played by Hurt that existed between the Doctor's Eighth and Ninth incarnations.

In the 2013 mini-episode "The Night of the Doctor", a prelude to the 50th anniversary special "The Day of the Doctor", it was revealed that the Eighth Doctor had been revived by the Sisterhood of Karn after dying in a spacecraft crash. The Sisterhood offered him an elixir that enabled him to choose the characteristics of his next regeneration, and he opted for "a warrior"; the final scene of the mini-episode shows him regenerating not into the Ninth Doctor, as had been widely assumed, but into the War Doctor, played in the final scene of "The Name of the Doctor" by John Hurt.

Davies's 2018 novelisation of his debut episode "Rose" states that the Doctor's future incarnations include "a tall, bald black woman wielding a flaming sword" and "a young girl or boy in a hi-tech wheelchair with what looked like a robot dog at their side".[63]

It was established in The Deadly Assassin (1976) that a Time Lord can regenerate twelve times before permanently dying – a total of thirteen incarnations. The 20th Anniversary special, the 1996 television film and 2013 special "The Time of the Doctor" all confirm this with the latter showing that the Time Lords can circumvent the cap of 12 regenerations in total by giving a Time Lord extra regenerations. While many of the previous regeneration sequences were unique, the Doctor's regenerations of the revived programme were similar with each transition being an explosion of energy in a particularly violent fashion. This can be seen from the Tenth Doctor's regeneration damaging the TARDIS, to the Eleventh Doctor's causing a shock wave that devastated the countryside while obliterating a Dalek mother-ship.

In the BBC Series 4 FAQ, writer Russell T Davies made a joke that now the Time Lord social order has been destroyed, the Doctor may be able to regenerate indefinitely: "Now that his people are gone, who knows? Time Lords used to have 13 lives."[26][64]

In "The Christmas Invasion" (2005), it was stated the regenerative cycle creates a large amount of residual regeneration energy that suffuses the Time Lord's body. As demonstrated by the Tenth Doctor for the first time in that story, in the first fifteen hours of regeneration this energy is enough to even rapidly regrow a severed hand.

In the case of the Doctor, his regenerations are usually a result of a previous incarnation sustaining mortal injury, though he can regenerate from old age and was once forced to regenerate by the Time Lords. A common side effect the Doctor frequently experiences is a period of instability and partial amnesia following regeneration. Some post-regeneration experiences have been more difficult than others. In particular, the Fifth Doctor began reverting to his previous personalities and required the healing powers of the TARDIS's "Zero Room" to recuperate (Castrovalva). The Sixth Doctor experienced extreme paranoia and flew into a murderous rage, nearly killing his companion (The Twin Dilemma). The Eighth Doctor experienced amnesia due to the anaesthetics affecting his physiology (1996 Doctor Who television film). While his regeneration first appeared to be smooth ("The Parting of the Ways"), the Tenth Doctor began to experience spasms and became somewhat manic, frightening his companion as he pushed the TARDIS to dangerous extremes (Children in Need mini-episode). After crash-landing the TARDIS, the Doctor collapsed and remained unconscious for most of the next fifteen hours ("The Christmas Invasion"). The experience was traumatic enough to cause one of his hearts to temporarily stop beating.

The TARDIS appears to aid in the regenerative process, with few occasions where the Doctor regenerates outside it. Three of these are initiated by Time Lords: one forced on him before banishment to Earth (The War Games), one requiring a Time Lord to give the Doctor's cells a "little push" to start the process (Planet of the Spiders), and one needing the Watcher – which the Doctor's travelling companions believed to be some version of the Doctor himself (Logopolis). The Eighth Doctor's regeneration apparently occurred a few hours after he had actually "died", leaving him with temporary amnesia due to his body's adverse reaction to earth medicines.

In "Journey's End", the Tenth Doctor manages to avert his own regeneration by using some of the energy to heal himself, then channeling the remaining energy into his severed hand, thus retaining his appearance and personality. That regenerative energy was a key point in a "human–Time Lord biological metacrisis" inadvertently caused by Donna Noble that creates the Meta-Crisis Doctor while she obtains a Time Lord intellect. Later in the series, during the events of "The Time of the Doctor" the Eleventh Doctor revealed that it was considered a full regeneration; he just kept the same face due to "vanity issues", and that he was now in his final (13th) life (given that the Tenth Doctor counted as two regenerations and the revelation of the existence of the War Doctor, this made a total of 12 regenerations). However, during the same episode, the Doctor is given a new cycle of regenerations by the Time Lords, allowing him to regenerate for the thirteenth time into the Twelfth Doctor, with the Twelfth Doctor ("Kill the Moon") and Rassilon ("Hell Bent") each expressing uncertainty about how many regenerations the Doctor now has.

Due to time travel, it is possible for the Doctor's various incarnations to encounter and interact with each other, although supposedly prohibited by the First Law of Time (as stated in The Three Doctors) or permitted only in the "gravest of emergencies" (The Five Doctors). In the 1963–1989 television programme, such encounters were seen on three occasions: in The Three Doctors (1972), The Five Doctors (1983) and The Two Doctors (1985). In Day of the Daleks (1972), the Third Doctor and Jo Grant very briefly met their future selves due to a glitch during a temporal experiment (the serial was supposed to end with the same scene depicted from the perspective of the "other" Doctor and Jo, but was excised because it was anticlimactic).[65] In "Father's Day" (2005), the Ninth Doctor and Rose observed but did not interact with past versions of themselves; when Rose changed history, the earlier selves – after momentarily noticing Rose running past – vanished and a temporal paradox was created that attracted the extra-dimensional Reapers. The Tenth and Fifth Doctors met in the TARDIS in the mini-episode "Time Crash", which aired on 16 November 2007 as part of the BBC's annual Children in Need appeal. This marks the first time the Doctor has met a previous incarnation since the programme's revival. Although the scene aired outside the programme itself, it was established as taking place between the events of "Last of the Time Lords" and "Voyage of the Damned".

In the Virgin New Adventures, the Seventh Doctor is shown briefly interacting with a man who may be the Third Doctor in the Sherlock Holmes crossover novel All-Consuming Fire, but the scene is narrated from the perspective of Dr. Watson and thus the other man is never expressly identified. The Virgin Missing Adventures novel Cold Fusion is a unique twist on the traditional multi-Doctor story as it focuses on the Fifth Doctor's adventures before he meets the Seventh, where normal stories treat the later Doctor as 'the' Doctor.

The BBC novel The Eight Doctors was written by respected Doctor Who writer Terrance Dicks, the same author who wrote The Five Doctors. In it, he tries to reconcile the continuity errors of the 1996 movie, while having the Eighth Doctor meet and interact with each of his previous selves, although the Eighth Doctor visited each incarnation one at a time rather than all eight of them appearing in the same place. Later Eighth Doctor novel Interference – Book One sees the Eighth Doctor briefly meeting the Third, although this occasion results in the Doctor unwittingly changing his own history so that the Third Doctor will regenerate ahead of schedule (A change that is later 'reset' in the novel The Ancestor Cell thanks to the TARDIS taking action to preserve the original history). In the Past Doctor Adventures, the novel Heart of TARDIS features the Second and Fourth Doctors dealing with two different ends of the same crisis, with the Second Doctor trapped in a dimensional anomaly created by a government experiment and the Fourth recruited to stop the experiment destroying the world, but although they are at one point both in the Second Doctor's TARDIS, the Fourth Doctor and his companion hide on the opposite side of the console from his past self and the Second is never aware of his future self. In The Colony of Lies, the Second Doctor briefly interacts with the Seventh Doctor in a VR simulation, but it is unspecified if this is the actual Seventh Doctor or just a VR program he left to advise his past self. In Wolfsbane, like in Heart of TARDIS, the Fourth and Eighth Doctors deal with separate ends of the same crisis, the Eighth stopping the threat in November 1936 while the Fourth ties up loose ends in December of the same year, but the two incarnations never meet directly, and due to the Eighth Doctor's current amnesia none of the other characters realizes that the two Doctors are the same person.

Physical contact between two versions of the same person in the programme can lead to an energy discharge that shorts out the "time differential". This is apparently due to a (fictional) principle known as the Blinovitch Limitation Effect, and was seen when the past and future versions of Brigadier Lethbridge-Stewart touched hands in Mawdryn Undead. The Doctor's incarnations do not appear to suffer this effect when encountering each other and shaking hands. This has never been explained. An essay in the About Time episode guides by Lawrence Miles and Tat Wood suggests that Time Lords are somehow exempt from the effect by their very nature. Rose Tyler is seen holding an infant version of herself in "Father's Day", with no visible energy discharge, but the contact does allow the Reapers to enter the church in which the Doctor and several others are taking refuge. While doing a live commentary on the episode at the 2006 Bristol Comic Expo, episode author Paul Cornell said that this is supposed to be due to the Blinovitch Limitation Effect, even though it is not mentioned by name. He suggested that the lack of a spark may be down to the fact that the Time Lords were no longer around to manage anomalies.

In the 2006 episode "School Reunion", the Tenth Doctor and Sarah Jane Smith both seem to indicate in dialogue that they haven't seen each other since her departure from the TARDIS in The Hand of Fear, although this contradicts their having met later during The Five Doctors. In that story, she does not appear to realise that the Fifth Doctor is a later incarnation of the third and fourth Doctors with whom she had previously travelled. In "Time Crash", the Tenth Doctor remembers and reproduces what he saw himself do when he was the Fifth Doctor, a fact that seems to surprise the Fifth Doctor himself.

Russell T Davies has expressed a dislike for stories in which multiple incarnations of the Doctor meet, stating that he believes they focus more on the actors than on the story itself.[66] In 2007, David Tennant showed enthusiasm for the idea of a multi-Doctor story but expressed doubts about the practicality of episodes involving multiple previous Doctors, given that three of the actors who played the character were deceased.[67]

The temporarily human Doctor, John Smith, draws his dreams of past incarnations in "Human Nature". (Left hand page: Tenth and Ninth; Right hand page, left to right, top to bottom: Fourth, Third, Second, Seventh, Eighth, First, Sixth, Fifth)

Since the programme's revival, there have been four multi-Doctor stories: the Children in Need special "Time Crash", the 50th-anniversary special, "The Day of the Doctor", the 2017 Christmas special "Twice Upon A Time", and the series 12 episode "Fugitive of the Judoon". Before that, the only references to past incarnations (from 1963 to 1996) have been in the aforementioned episode "School Reunion" (in which the Doctor acknowledges having regenerated "half a dozen times" since last seeing Sarah Jane) and in drawings that the Doctor (who has temporarily become human to hide from the Family Of Blood) makes based on dreams of his other life in the 2007 episode "Human Nature". Seen on screen are the First, Fifth, Sixth, Seventh and Eighth Doctors, but a fuller view briefly available on the BBC website depicted all ten incarnations. In the 2008 Christmas episode, The Next Doctor, the Tenth Doctor discovers an info stamp originally held by the Cybermen, which includes images of all his past selves. This is a clear affirmation of his past, and that the (then) current incarnation was indeed the Tenth. This was reaffirmed in the episode "The Eleventh Hour", when the Doctor asks the Atraxi whether this planet is protected. The Atraxi then shows 10 images, one of each Doctor from the first to the tenth, with the eleventh walking through the image of the tenth at the end. This is confirmed in the episode "The Lodger", when the Doctor, explaining to Craig who and what he is, points at his face and says, "Eleventh."

Because each new Doctor is different from their previous incarnations, how their personalities interact varies when two or more different incarnations encounter each other. Time Crash featured Peter Davison returning as the Fifth Doctor. This event is explained as occurring due to the current Doctor having left his shields down when rebuilding the TARDIS following "Last of the Time Lords" and then accidentally crossing the Fifth Doctor's timeline, allowing the two TARDISes to merge. When the Tenth Doctor effortlessly averts the impending Belgium-sized hole in the Universe caused by this temporal anomaly, he reveals having known what to do because he saw himself do it as the Fifth Doctor and remembered. He goes on to tell the Fifth Doctor how fond he was of his incarnation and how he influences the current Doctor's personality. However, in their two meetings, the Second Doctor and Third Doctor had a degree of antagonism towards each other, with the patriarchal First Doctor critical of them both. During the Virgin New Adventures, the Seventh Doctor was occasionally at odds with his subconscious memory of his previous incarnation as his memory of his past self became increasingly associated with the Valeyard, his dark, future self, but he eventually accepted his dark side and 'reformed' his memory of his former self, although it was never established how the two Doctors would interact if they had met in person.

On many occasions the Eleventh Doctor has actually encountered himself from a different point in his timeline – in "The Big Bang", the mini-episodes "Space" and "Time" and "Last Night" – and in "Journey to the Centre of the TARDIS", at the end, the Doctor interacted with his past self to reset time. In all stories, multiple versions of the Eleventh Doctor from different timelines meet and carry on brief conversations. Additionally, the Eleventh Doctor encountered an artificial (though physically and mentally identical) copy of himself in "The Almost People"; fought against "Mister Clever", an artificial personality generated out of his own by the Cybermen in "Nightmare in Silver"; and was pitted against "The Dream Lord", a manifestation of his self-loathing and anger, in "Amy's Choice".

Later, the Eleventh Doctor entered his own timeline in "The Name of the Doctor" to rescue his companion Clara Oswald, and while there observed a past incarnation portrayed by John Hurt, one whose actions caused him to be unworthy of the name "Doctor" and viewed as shameful by his future selves. In the 50th anniversary special, "The Day of the Doctor", the Eleventh Doctor encounters both the Tenth Doctor and the War Doctor (played by John Hurt). The Tenth and Eleventh Doctors are generally amicable towards each other, despite bickering,[68] although the War Doctor treats them both as behaving too childishly. Despite this, he does come to admire both of his future incarnations, working together with them and eventually choosing to go through with the act of destroying Gallifrey because he knows it will help them become what they are. The Tenth and Eleventh are initially leery of the War Doctor, the Eleventh describing him as the "one life I have tried very hard to forget." However, both of them later recognise that the War Doctor followed what seemed to be the only course open to him, and are even willing to help him carry it out so that he won't have to suffer the guilt alone. Fortunately, with influence from the Moment – a sentient Time Lord weapon that brought about their meeting – the three are able to stumble upon an alternative: sending Gallifrey into a pocket universe, making it seem as though it has been destroyed. The three are then joined by the other nine previous Doctors and the future Twelfth Doctor (Peter Capaldi) in this act (the War, Tenth and Eleventh Doctors having evidently contacted them off-screen). The Eleventh Doctor is shown to have memories of these events but only recalls them after they have begun. This is explained in dialogue as an instability in the timeline, which causes the War and Tenth Doctors to forget their meeting, thus maintaining the continuity in which the Doctors from the War Doctor onwards believe themselves to have destroyed Gallifrey.

The Thirteenth Doctor meets a previously unknown incarnation of the Doctor portrayed by Jo Martin in "Fugitive of the Judoon". It is implied in "The Timeless Children" that Martin's Doctor was a previous incarnation that had been erased from the Doctor's memory by the Division.

On a few occasions, previous actors to have played Doctor have returned to the role, usually guest-starring with the incumbent:

• William Hartnell and Patrick Troughton with Jon Pertwee in The Three Doctors. Originally Hartnell's role had been intended to be more extensive, but his health had deteriorated to the extent that he could only make a limited appearance which would be his last television role.
• Troughton and Pertwee with Peter Davison in The Five Doctors, the twentieth anniversary special, with newly released footage of Tom Baker and another actor, Richard Hurndall, standing in for the deceased William Hartnell. Archive footage of Hartnell taken from The Dalek Invasion of Earth introduced the story. Baker declined to appear, feeling that the role came too soon after he had left the programme (a decision he later said he regretted)[69] and the narrative was reworked to use clips from Shada, an intended six-part story from the Fourth Doctor's era that was never completed due to industrial strikes. A waxwork dummy of Baker from Madame Tussauds was used in publicity photographs.
• Patrick Troughton with Colin Baker in The Two Doctors. This story is notable for not being produced either to celebrate the programme's anniversary or as a Children in Need production.
• Sylvester McCoy was joined by Jon Pertwee, Tom Baker, Peter Davison and Colin Baker, with the first and the second Doctor being represented by rubber heads, because both actors had died by then, in Dimensions in Time, the programme's thirtieth-anniversary charity special in aid of Children in Need in 1993. Except for the mannequin versions of Hartnell and Troughton, no two Doctors are shown on screen at the same time. (This story was a crossover with EastEnders).
• Sylvester McCoy returned to film early segments of Doctor Who, the TV film featuring the Seventh Doctor's regeneration scene.
• Peter Davison with David Tennant in the 2007 Children in Need special "Time Crash".
• Paul McGann returned to film the Eighth Doctor's final moments and regeneration in the 2013 mini-episode "The Night of the Doctor", a prelude to the 50th anniversary special "The Day of the Doctor". None of the other Doctors appeared in this mini-episode, although archive footage of John Hurt appears briefly in the closing scene, for which he provided original audio.
• David Tennant appeared in the 50th anniversary special "The Day of the Doctor" with Matt Smith. Also co-starring was John Hurt as a newly revealed incarnation of the Doctor. Tom Baker had a cameo appearance in the special as the curator of the National Gallery. He was implied to be a future Doctor who was "revisiting" an "old favourite" face, but the script never explicitly states this. Dialogue states that "perhaps it doesn't matter either way" whether the Doctor and Curator are the same individual. Archive footage of the original eight Doctors was reworked with new audio from voice actor John Guilor, and a brief appearance by future Doctor actor Peter Capaldi was inserted, to represent all (then) thirteen incarnations of the Doctor.
• Matt Smith made another appearance in "Deep Breath", the first full episode after his regeneration. He made a telephone call to his future to reassure Clara Oswald and urge her to accept his successor, portrayed by Peter Capaldi. The scene was filmed on the set of "The Time of the Doctor", Smith's last story as the incumbent Doctor, for the eighth series.[70]
• Peter Davison, Colin Baker, Sylvester McCoy and Paul McGann appeared in "The Power of the Doctor" as spirit forms of their Doctors who interact with the Thirteenth Doctor. Davison and McCoy also appeared as holographic versions of their incarnations, when the Thirteenth Doctor talks to Tegan Jovanka and Ace.
• David Tennant appeared as the Fourteenth Doctor[71][72] in "The Power of the Doctor" and is set to star in the 60th anniversary specials in 2023.

In addition to the above, Tom Baker, Davison, Colin Baker, McCoy, McGann, Hurt, Eccleston and Tennant have reprised the role in audio dramas from Big Finish Productions.

The very first episode of the television programme established that Susan Foreman is the Doctor's granddaughter, but neither Susan nor the Doctor ever speaks of her parents.

The First Doctor did flirt with – and was accidentally engaged to – the character Cameca in The Aztecs (1964). Although this was part of a plot to get the TARDIS back, there was a hint of mutual attraction in Hartnell's performance (especially as he is ultimately unable to leave behind the love token she has given him).

The Third Doctor expresses hurt feelings when his companion Jo Grant leaves him for an idealistic scientific adventurer whom she describes as "a younger version" of the Doctor (The Green Death). Jo kisses the Doctor on the cheek before she departs, the second time this form of affection had been shown on screen (the Second Doctor having similarly kissed Zoe in The War Games).

There was on-screen chemistry between Fourth Doctor Tom Baker and his wife-to-be Lalla Ward's Second Romana. A 1980 television commercial broadcast in Australia for Prime Computers showed Baker and Ward romancing each other, in character as the Doctor and Romana, with the Doctor (prompted by the computer) proposing marriage.[81]

In voiceovers on Peter Davison's DVDs, the matter of physical affection is discussed. According to Davison and Matthew Waterhouse (Adric), producer John Nathan-Turner had very strict rules laid down about how the companions were allowed to physically interact with the Doctor, and Adric was allowed more physical contact with the Doctor than the female companions to downplay potential romantic and/or sexual connotations.

Beginning in 2005 the programme has suggested that the Doctor has romantic feelings towards different people. This shift is satirised in "The Day of the Doctor" wherein the War Doctor, having witnessed a passionate kiss exchanged between his tenth incarnation and Queen Elizabeth I, asks of the eleventh, "Is there a lot of this in the future?" to which he replies, "It does start to happen, yeah."

The series has played with the idea of a romantic relationship between the Ninth Doctor and Rose Tyler, with many characters assuming they were a couple. Rose's boyfriend Mickey Smith clearly views the Doctor as a romantic rival for whom Rose has left him. Each shows flashes of jealousy when the other flirts with other characters. In "The Parting of the Ways" (2005), the Doctor's male companion Jack Harkness kisses both the Doctor and Rose in what he believes is a last goodbye. In the same episode, the Doctor kisses Rose Tyler to get the time vortex energy that was killing her back into the TARDIS, subsequently "killing" him and causing his next regeneration.

In the New Series Adventures novel Only Human by Gareth Roberts, Rose asks the Doctor how he would know that marrying for love is overrated, to which he cryptically answers, "Who says I don't? You ask the Lady Mary Wortley Montagu." In a December 2005 interview on BBC Four, actor David Tennant, who had just taken the role of the Tenth Doctor, described the relationship between the Doctor and Rose as "basically a love story without the shagging". He later stated that Rose was the Doctor's girlfriend, though it was never explicitly stated on screen.[82]

The Doctor's relationship with Rose intensifies after he regenerates into the Tenth Doctor. In "New Earth" (2006), Rose's body is temporarily inhabited by Cassandra, who kisses the Doctor romantically. This is one of the few scenes in the entire programme where the Doctor is kissed romantically by his companion. In "School Reunion" (2006), the arrival of the Doctor's previous companion Sarah Jane Smith and his reaction to seeing her again prompts jealousy and worry from Rose, and Sarah all but admits that she has long been in love with the Doctor. The Doctor also expresses dismay at having his companions age while he regenerates. In the episode, "The Girl in the Fireplace" (2006) (written by Steven Moffat), the Doctor develops a romantic relationship with Madame de Pompadour, with whom he shares a passionate kiss. She even takes him away to "dance", but how far the metaphor (coined in the episode "The Doctor Dances") is taken is not seen on screen. Rose does not openly exhibit jealousy towards Madame de Pompadour. In the novel The Stone Rose, by Jacqueline Rayner, the Doctor kisses Rose after she saves him from being petrified, with it being described as "a kiss of gratitude and joy and unspeakable pleasure at being alive". In "The Impossible Planet" (2006), the Doctor and Rose share an awkward moment when they have to consider settling down in one time period and Rose suggests they do so together. She later plants a kiss for good luck on the Doctor's spacesuit prior to his descent into the pit. In "The Satan Pit" the Doctor, fearing for his life, tells someone "If you see Rose, tell her... tell her... oh, she knows." In "Doomsday", when the Doctor says his goodbye to Rose, she finally tells him that she loves him. He begins to reply, but the message is cut off, and he is unable to reciprocate; in the episode's audio commentary, executive producer Julie Gardner had stated that "he absolutely was going to say it... he was going to tell her he loved her."[83]

Executive producer Russell T Davies states in Doctor Who Confidential that the reunion between the Doctor and Rose in the 2008 episode "The Stolen Earth" is a parody of romantic film conventions because the heightened emotional content is abruptly interrupted by the Doctor being shot by a Dalek. In the next episode, "Journey's End", Rose challenges the Doctor to say what he did not get to say before, to which he replies, "Does it need saying?" His half-human duplicate, however, does whisper it into Rose's ear, and the two of them kiss; Rose gets an emphatically romantic resolution to her romance storyline, as the duplicate Doctor and Rose continue to live together on a parallel Earth. Gardner commented in Confidential that although the audience cannot hear, it is obvious that he is saying "I love you".[84]

Throughout series three (2007), companion Martha Jones pines for the Doctor's affection following a kiss between them which was only used as a "genetic transfer" to distract their pursuers. She is distraught when, temporarily turned into a human in "Human Nature", the Doctor's human persona, John Smith, falls in love with nurse Joan Redfern. She admits in "The Family of Blood" to Smith that "[the Doctor] is everything to me, and he doesn't even look at me, but I don't care, because I love him to bits, and I hope to God he won't remember me saying this". The Doctor tells Joan he is capable of everything that Smith was, but she rejects his attempt to establish a relationship with her as the Doctor. In the following episode, "Blink", he refers to being "rubbish at weddings, especially my own". Martha eventually quits as the Doctor's full-time companion in the series finale "Last of the Time Lords" because she is in love with the Doctor and he seems unable or unwilling to reciprocate; she received similar commiseration from Jack Harkness, who is also infatuated with him, in "The Sound of Drums".

Subsequently, in the 2008 series, the Doctor's friendship with Donna Noble is strengthened, after the infatuations with Martha and Rose, by the knowledge that she has no romantic interest in him whatsoever. Davies' last clear allusion to the Doctor's romantic capacity occurs at the beginning of his last episode as showrunner, "The End of Time". The Tenth Doctor claims to have married "Good Queen Bess, and let me tell you, her nickname is no longer... (clears throat)", a reference to Elizabeth I of England's nickname "The Virgin Queen". The marriage, which is referred to as "a mistake", explained Queen Elizabeth's reaction to seeing the Tenth Doctor in an earlier episode, "The Shakespeare Code". Subsequent episodes have alluded to this romantic, possibly sexual relationship. This relationship, including the marriage and the "mistake" that led to it (a case of mistaken identity involving a Zygon commander in 1562), eventually unfolds on screen in "The Day of the Doctor".

In "The Next Doctor" he tells Jackson Lake that his companions "break [his] hearts".

Episodes written by Steven Moffat have continued to hint at the Doctor's romantic capacity: his stories during the Russell T Davies tenure as showrunner included the admission of a sex life in "The Doctor Dances" and the romance with Madame de Pompadour in "The Girl in the Fireplace", past marriages in "Blink", and the introduction of recurring character River Song in the 2008 episodes "Silence in the Library"/"Forest of the Dead", who indicates she is a lover of the Doctor. In his tenure as showrunner (2010–2017), the series continued to imply that the Doctor will have a relationship with, and perhaps marry, River Song. Additionally, Moffat has companion Amy Pond attempt to seduce the Doctor in "Flesh and Stone", although he expresses shock at the idea, protesting that she was human. In "A Christmas Carol", the Eleventh Doctor finds himself accidentally engaged to film star Marilyn Monroe during a visit to 1950s Hollywood. The Doctor's past romantic relationship with Elizabeth I is alluded to in Moffat episodes "The Beast Below" and "The Wedding of River Song", as well as in "Amy's Choice" by Simon Nye.

In her 2010 appearances, River continues to hint at a relationship with the Doctor in her relative past and his relative future. In "The Big Bang", River suggests to the Doctor that she is married to him in his personal future. When River kisses the Doctor in "Day of the Moon", it becomes clear that whereas this is the Doctor's first kiss with her, it is to be her last with him and that she shall soon be heading to The Library where she dies. In "A Good Man Goes to War", River is seen returning from a date with the future Doctor, and repeatedly calls the present-day Doctor "my love". In "Let's Kill Hitler", a young River Song compares herself to Mrs. Robinson and kisses the Doctor; the first time in an attempt to kill him, the second to save his life. Later she resolves to study archaeology so that she can encounter the Doctor again. Because she loves him, she refuses to shoot him in "The Wedding of River Song", creating an alternate timeline. In this world, the Doctor marries River in a very brief ceremony witnessed by Amy and Rory, so that he may allow time to return to normal and go to his death, while secretly disclosing to River that he will fake his death. Although the alternate timeline is erased, all future episodes act as though the wedding was real. Later, when Dorium comments that River is incarcerated in the Stormcage for "all her days", the Doctor responds "Her days, yes, her nights...well...that's between her and me". After this episode, the banter and gentle sexual innuendo between them becomes less teasing and more serious.

Later, in "The Name of the Doctor" (2013), the Doctor kisses a holographic projection of River Song, based on the copy of her mind archived in the great Library of the 51st century. During this episode, both the Doctor and River call her his wife. He reveals that the reason he has avoided mentioning her since her death was for fear that the memory would hurt too much – as River notes to colleagues, "he hates endings". After this exchange, he bids her a final farewell – but at her request – phrasing it with the implication that they may meet again.

Despite this, the Doctor's limited understanding of human romance and sexuality has been the subject of many jokes. For example, in "Flesh and Stone", after being kissed by Amy Pond, his first response is to gasp, "But you're human!", and he later blithely mentions this embrace to her fiancé Rory in the following episode, "The Vampires of Venice", not realising this would upset Rory. In "The Doctor's Wife", when he tells Amy and Rory that he is redoing the TARDIS's guest room, they suggest, "Perhaps not bunk beds this time," and he does not understand why a married couple would not find bunk beds preferable to other furniture. In "A Good Man Goes to War", he is asked about Amy and Rory's sex life and refers to it as "private human stuff".

In "The Time of the Doctor" (2013), it is revealed that the Doctor, in an unspecified prior incarnation to the Eleventh, engaged in a romance with a woman named Tasha Lem. Their attraction appeared to continue when the Eleventh encountered her again, even after Lem was technically killed and made into a Dalek-human hybrid.

At first, the Twelfth Doctor explicitly rejected the idea of having a romantic relationship with his companion Clara Oswald. He implied that in his previous form, he had come to see himself as Clara's "boyfriend" in an attempt to avoid confronting his extreme age and alien nature.[85] Initially it was reported that Peter Capaldi told tabloids there would be "no flirting" between him and Clara, likening such a potential relationship to Papa and Nicole, but the actor himself discarded that.[86][87] The episode "Deep Breath" introduces a character named Missy who identifies the Doctor as her boyfriend. Missy is later revealed to be a female incarnation of the Master. As the character of the Twelfth Doctor evolved, so did his relationship with Clara. In a spring 2015 interview, Steven Moffat indicated that the Doctor had never stopped being "besotted" with Clara, and that he "loves them (companions) more than they love him."[88] In a media roundtable interview at the 2015 San Diego Comic Con, Capaldi went further, saying the two were romantically involved, just not in the traditional sense, "It's romantic in the old sense. Two people who are really crazy about each other..."[89] The narrative of series nine culminated in a three-part story arc in which Clara dies and the Doctor spends the next 4.5 billion years executing a gambit to change history and save her life. Further romance for the Twelfth Doctor was depicted in the 2015 Christmas special, "The Husbands of River Song", which had a romantic plot. In the special, the Twelfth Doctor meets his one-time wife, River Song, for the first (and, narratively, the last) time.

Later, now as a woman, the Thirteenth Doctor experienced her first on-screen same-sex romantic situation with companion Yasmin Khan. Yaz admits her feelings in "Eve of the Daleks" (2022). The Doctor confronts Yaz about them in "Legend of the Sea Devils", saying she reciprocated Yaz's affection while refusing to become involved with another human companion who will one day die.

The spin-off media both before and after the television movie have toyed with the idea in various ways. In the 1995 Virgin New Adventures novel Human Nature by Paul Cornell, the Seventh Doctor takes on the human guise of "Dr John Smith" and has a romance with a teacher named Joan in 1914, albeit as a means to understand the human condition and with the Doctor's own memories as a Time Lord suppressed. The relationship ended when the Doctor was restored to normal, admitting to Joan that he knows that Smith was fond of her but unable to reciprocate those feelings himself. This novel was adapted to the screen and comprised two episodes in the new programme: "Human Nature" and "The Family of Blood", featuring the Tenth Doctor, with the Doctor implying that he retained Smith's feelings for Joan, although the more traumatic nature of the transformation may have impacted his feelings after he returned to normal.

In the Virgin novel Death and Diplomacy, by Dave Stone, the Seventh Doctor implies that he intentionally creates an image of asexuality to keep things simple.

The concluding chapter of The Dying Days, an Eighth Doctor novel by Lance Parkin, strongly implies intimacy occurring between the Doctor and Bernice Summerfield. This encounter was later confirmed in the audio drama "Benny's Story", a chapter of the Big Finish Productions release The Company of Friends, marking the only time to date that a classic-era Doctor has been confirmed as sleeping with one of his companions.

Writer Lawrence Miles has stated that he believes the Eighth Doctor has sex with I. M. Foreman between the events of his novels Interference – Book One and Interference – Book Two.[90] In Book Two, the Doctor explains that he has become interested in romance and the idea of being close to someone in his current body, but that he is reluctant to explore these feelings with his companions because of the emotional baggage a relationship with him would bring.

In various novels – especially Lungbarrow – it is established that Time Lords do not reproduce sexually, but emerge from genetic Looms fully grown, though the same book hints that the Doctor's birth was an exception (unlike his cousins, he has a belly button). Lance Parkin's novels Cold Fusion (1997) and The Infinity Doctors (1998) suggest that "wombborn" families have survived in secret, and that the Doctor and the Master were born to these families. In the 1996 film Doctor Who, the Doctor states he is "half-human, on [his] mother's side", which the Master also affirms. The revived programme portrays Time Lord children, with a child version of the Doctor appearing in the 2014 episode "Listen".

In the Big Finish Productions audio play Loups-Garoux, the Fifth Doctor reluctantly agrees to marry the werewolf Ileana De Santos and although he gets out of it later, as in Cameca's case, a degree of mutual attraction is present. In the audio plays involving the Eighth Doctor, his companion Charley confesses her romantic feelings for him in Zagreus, but although he admits he loves her at the time, it is a highly dramatic moment and the relationship does not progress beyond the platonic.

The recurring novel and audio character Iris Wildthyme, created by Paul Magrs, is first introduced in the Short Trips story Old Flames, is a past romantic interest of the Doctor's who continues to flirt with him whenever they meet. More of the Doctor's past relationships are explored in The Infinity Doctors and Cold Fusion.

The question of romance is sometimes sidestepped with plot devices in the spin-off media. In the 2001 BBC Books novel Father Time by Lance Parkin, the Doctor adopts an orphaned Gallifreyan-like alien called Miranda. It is implied in the book that Miranda is actually the daughter of the Doctor himself from the far future. Miranda returns in the novel Sometime Never... by Justin Richards, with her own daughter Zezanne. At that novel's end, a time-active being called Soul travels into the past accompanied by Zezanne, the two believing themselves to be the Doctor and Susan, respectively.

In The One Doctor, the Doctor kisses Sally-Anne Stubbins to bluff to the Sussyurat that he was not the Doctor but Banto Zane, but this kiss showed no affection.