Calydon (Greek Καλυδών) was an ancient Greek city in Aetolia, situated on the west bank of the river Evenus.

According to Greek Mythology, the city took its name from its founder Calydon, son of Aetolus. Close to the city stood Mount Zygos, the slopes of which provided the setting for the hunt of the Calydonian Boar.

The city housed the important Aetolian sanctuary known as the Laphrion, dedicated to Artemis Laphria and Apollo Laphrios.

In 31 BC the Roman Emperor Octavian removed the population of the city to the new colony of Nicopolis, founded to commemorate his victory at the Battle of Actium earlier that year. At the same time the Romans removed most of the art and treasures of the city to Patras, including the gold and ivory cultic statue of Artemis.

Strabo, in his Geographia, comments on the former beauty of Calydon, which by his time lay desolate: '...Calydon and Pleuron, which are now indeed reduced, though in early times these settlements were an ornament to Greece.'