List of heads of state of Greece

Following the resignation of Augustinos Kapodistrias, a series of collective governing councils were established, but their authority was often only nominal.

The London Conference of 1832 was an international conference convened to establish a stable government in Greece. Negotiations between the three Great powers (United Kingdom, France and Russia) resulted in the establishment of the Kingdom of Greece under a Bavarian Prince. The decisions were ratified in the Treaty of Constantinople later that year.

The convention offered the throne to the Bavarian Prince, Otto. They also established the line of succession which would pass the crown to Otto's descendants, or his younger brothers should he have no issue. It was also decided that in no case there would be a personal union of the crowns of Greece and Bavaria. Otto went on to rule Greece until he was exiled in the 23 October 1862 Revolution.

King			Reign			Claim
No.	Portrait	Name (Birth–Death)	Reign start	Reign end	Duration
1		Otto Όθων (1815–1867)	27 May 1832 [1]	23 October 1862 (Deposed)	30 years, 149 days	Ascended to the throne following the 1832 London Conference

In October 1862, King Otto was deposed in a popular revolt, but while the Greek people rejected Otto, they did not seem averse to the concept of monarchy per se. Many Greeks, seeking closer ties to the pre-eminent world power, Great Britain, rallied around the idea that Prince Alfred, the second son of Queen Victoria and Prince Albert, could become the next King. British Foreign Secretary Lord Palmerston believed that the Greeks were "panting for increase in territory", hoping that the election of Alfred as King would also result in the incorporation of the Ionian Islands, which were then a British protectorate, into an enlarged Greek state.

The London Conference of 1832, however, had prohibited any of the Great Powers' ruling families from accepting the crown of Greece, and in any event, Queen Victoria was adamantly opposed to the idea. Nevertheless, the Greeks insisted on holding a referendum on the issue of the head of state in November 1862. It was the first referendum ever held in Greece.

Prince Alfred turned down the Kingship and Prince William of Denmark, son of Prince Christian of Denmark, was elected by the National Assembly to become King George I of the Hellenes.

King			Reign			Claim
No.	Portrait	Name (Birth–Death)	Reign start	Reign end	Duration
2		George I Γεώργιος A΄ (1845–1913)	30 March 1863	18 March 1913 (Assassinated)	49 years, 353 days	Ascended to the throne following the 19 November 1862 referendum
3		Constantine I Κωνσταντίνος A΄ (1868–1923)	18 March 1913	11 June 1917 (Abdicated)	4 years, 85 days	Son of George I
4		Alexander Αλέξανδρος (1893–1920)	11 June 1917	25 October 1920	3 years, 136 days	Second son of Constantine I
—		Admiral Pavlos Kountouriotis Παύλος Κουντουριώτης (1855–1935)	28 October 1920	17 November 1920 (Resigned)	20 days	Regent
—		Queen Olga Βασίλισσα Όλγα (1851–1926)	17 November 1920	19 December 1920	32 days	Regent Widow of George I Mother of Constantine I
(3)		Constantine I Κωνσταντίνος A΄ (1868–1923)	19 December 1920	27 September 1922 (Abdicated)	1 year, 282 days	Restored to the throne following the 22 November 1920 referendum
5		George II Γεώργιος Β΄ (1890–1947)	27 September 1922	25 March 1924 (Deposed)	1 year, 180 days	Eldest son of Constantine I