380s BC

• A Spartan expeditionary force under King Agesilaus II crosses the Gulf of Corinth to attack Acarnania, an ally of the anti-Spartan coalition. Agesilaus is eventually able to draw them into a pitched battle, in which the Acarnanians are routed.
• The Athenian general, Thrasybulus, leads a force of triremes to levy tribute from cities around the Aegean and support Rhodes, where a democratic government is struggling against Sparta. On this campaign, Thrasybulus captures Byzantium, imposes a duty on ships passing through the Hellespont, and collects tribute from many of the Aegean Islands.
• Due to threats of attack from Akarnania, Kalydon garrisons the Achaeans.[1]
• The orator Isaeus gives his earliest known speech, the Dicaeogenes.[2]
• Magna Grecia
  • Battle of the Elleporus and the capture of Kroton by Dionysius I of Syracuse

• Wu Qi, the prime minister of the State of Chu, enacts his first series of political, municipal, and martial reforms. Wu Qi gains the ire and distrust of Chu officials and aristocratic elite who are against his crusades to sweep up corruption in the state and limit their power. He is eventually assassinated in 381 BC at the funeral of King Diao of Chu, although his assassins are executed shortly after by the newly enthroned King Su of Chu.
• This is the latest possible date for the compilation of the historical text Zuo Zhuan, attributed to a blind historian known as Zuo Qiuming.

• King Agesipolis I leads a Spartan army against Argos. Since no Argive army challenges him, he plunders the countryside for a time, and then, after receiving several unfavorable omens, returns to Sparta.
• The Athenian general, Thrasybulus, sails to Lesbos, where, with the support of the Mytileneans, he defeats the Spartan forces on the island and wins over a number of cities. While still on Lesbos, however, Thrasybulus is killed by raiders from the city of Aspendus where his financial exactions have made him unpopular.
• Concerned about the revival of Athenian imperialist ambitions, the Persian King Artaxerxes II and King Agesilaus II of Sparta enter into an alliance. Sparta also seeks and gains the support of Dionysius I of Syracuse.

• Plato, having left Athens on Socrates' death to visit Megara and possibly Egypt, travels to Syracuse at the invitation of Dionysius I's brother-in-law Dion.
• Aristophanes' play Plutus is performed.

• End of the Corinthian War:

• Peace of Antalcidas (or "the king's peace") is brokered by Artaxerxes II. Under the Peace, all the Asiatic mainland and Cyprus remain under Persian control, Lemnos, Imbros, and Scyros remain Athenian dependencies, and all the other Greek states are to receive autonomy. By the King's Peace, the Persians become key players in Greek politics.
• Under the threat of Spartan intervention, Thebes disbands its league, and Argos and Corinth end their shared government. Corinth is incorporated back into Sparta's Peloponnesian League.

• Plato founds the Platonic Academy in Athens, where he teaches Aristotle until 347 BC.

• With the aid of the Lucanians, Dionysius I of Syracuse devastates the territories of Thurii, Crotone, and Locri in mainland Italy. When Rhegium falls, Dionysius becomes the chief power in Greek Southern Italy. He then turns his attention to the Adriatic and founds the colonies of Ancona (Ankon) and Adria (Adrìa).
• Plato is forced by Dionysius to leave Syracuse after having exercised the right of free speech too broadly. Plato returns to Athens, outside which he founds a school.

• Rome begins to rebuild after being invaded by the Gauls under Brennus.
• Marcus Furius Camillus introduces the Capitoline Games (Ludi Capitolini) in honour of Jupiter Capitolinus, and in commemoration of Rome's Capitol not being captured by the Gauls.

• Freed from Spartan attacks by the King's Peace of the previous year, Persia turns to quieting Cyprus and Egypt. Owing to the skill of King Evagoras of Cyprus and of Egypt's Greek mercenary general Chabrias, these wars drag on for the rest of the decade.

• Dionysius I of Syracuse extends the influence and trade of Syracuse to the Adriatic, establishing colonies at Adria, Ancona and Issa.

• The Chinese city of Handan is founded by the State of Zhao.

• Jason of Pherae becomes tyrant of Thessaly.
• Dionysius I of Syracuse attempts to restore Alcetas I of Epirus to the throne.
• Bardyllis becomes king of Illyria and the Dardani and establishes the Bardyllian Dynasty.

• Plato forms his Academy, teaching mathematics, astronomy and other sciences as well as philosophy. It is dedicated to the Attic hero Academus. Philanthropists bear all costs; students pay no fees.

• Democritus announces that the Milky Way is composed of many stars.[3]

• Lysias, the Athenian orator, on the occasion of the Olympiad, rebukes the Greeks for allowing themselves to be dominated by the Syracusan tyrant Dionysius I and by the barbarian Persians.
• The Greeks found the colony of Pharos at the site of today’s Stari Grad on the island of Hvar, defeating Iadasinoi warriors brought in for its defense.

• King Amyntas III of Macedon, forms a temporary alliance with the Chalcidian League, a confederation of cities of the Chalcidice peninsula, east of Macedonia. Sparta, whose policy is to keep Greeks disunited, sends an expedition northwards to disrupt the Chalcidian League.
• The Spartan commander Phoebidas, who is passing through Boeotia on campaign, takes advantage of civil strife within Thebes to gain entrance to the city for his troops. Once inside, he seizes the Cadmeia (the citadel of Thebes), and forces the anti-Spartan party to flee the city. The government of Thebes is placed in the hands of the pro-Spartan party, backed by a Spartan garrison based in the Cadmeia. Many of the previous leaders of Thebes are driven into exile. Epaminondas, although associated with the anti-Spartan faction, is allowed to remain.

• The 19 year lunar cycle is introduced into the Babylonian calendar.

• The second Buddhist council is convened by king Kalasoka and held at Vaisali.

• Pelopidas, a Theban general and statesman, flees to Athens and takes the lead in attempts to liberate Thebes from Spartan control.
• In punishment for his unauthorized action in the previous year of taking over Thebes, Phoebidas is relieved of his command, but the Spartans continue to hold Thebes. The Spartan king Agesilaus II argues against punishing Phoebidas, on the grounds that his actions had benefited Sparta, and this was the only standard against which he ought to be judged.
• Evandrus takes over being Archon of Athens from Phanostratus.

London

• Ollivanders, Makers of Fine Wands, established.

• The Persian generals Tiribazus and Orontes invade Cyprus, with an army far larger than any King Evagoras of Cyprus could raise. However, Evagoras manages to cut off this force from being resupplied, and the starving troops rebel. However, the war then turns in the Persians' favour when Evagoras' fleet is destroyed at the Battle of Citium (Larnaca, Cyprus). Evagoras flees to Salamis, where he manages to conclude a peace which allows him to remain nominally king of Salamis, though in reality he is a vassal of the Persian king.

• Sparta increases its hold on central Greece by reestablishing the city of Plataea, which Sparta formerly destroyed in 427 BC.

• The district of Tusculum is pacified after a revolt against Rome, and then conquered. After an expression of complete submission to Rome, Tusculum becomes the first "municipium cum suffragio", and thenceforth the city continues to hold the rank of a municipium.

• Persia forces the Athenians to withdraw their general Chabrias from Egypt. Chabrias has been successfully supporting the Egyptian Pharaohs in maintaining their independence from the Persian Empire.

• The Egyptian Pharaoh Hakor dies and is succeeded by his son Nepherites II, but the latter is overthrown by Nectanebo I within the year, ending the Twenty-ninth dynasty of Egypt. Nectanabo (or more properly Nekhtnebef) becomes the first Pharaoh of the Thirtieth dynasty of Egypt.

• Cleombrotus I succeeds his brother Agesipolis I as king of Sparta.

• What some historians call the Rich style in Greece comes to an end.