The Battle of Potidaea occurred in 432 BC during the Peloponnesian War. The army of Athens defeated the army of Corinth and its allies at Potidaea in the first land battle of the war.
The Corinthian colony of Potidaea was a part of the Delian League before the war, paying tribute to Athens. After the Battle of Sybota, Athens demanded that Potidaea pull down part of its walls, expel the Corinthian ambassadors, and send hostages to Athens, fearing that the city would revolt with support from Corinth and Macedon. Archestratus was sent with 30 ships and 1,000 hoplites to campaign against Potidaea, having originally been sent to fight against the Macedonians. The Athenians joined with other allied forces and attacked Potidaea, and Aristeus' wing of Corinthian troops defeated a section of the Athenian line, although the Athenians emerged victorious elsewhere. Aristeus retreated along the sea coast, and relief forces were also defeated by the Athenians. The Macedonian forces did not join the battle, and the Athenians proceeded to blockade Potidaea, leading to a formal declaration of war on Athens by Corinth and Sparta. Among the veterans of the battle was Socrates, who saved the life of Alcibiades.