Megara (Greek: Μέγαρα; see also List of traditional Greek place names) is an ancient city in Attica, Greece. It lies on the Saronic Gulf opposite the island of Salamis, which belonged to Megara in archaic times, before being taken by Athens. Megara was one of the four districts of Attica, embodied in the four mythic sons of King Pandion II, of whom Nisos was the ruler of Megara.

In Greek mythology, Megara (in Greek: Μεγάρα) was the oldest daughter of Creon, king of Thebes. She married Heracles and later his nephew Iolaus. There is a poem about her, usually attributed to Moschus.