In Greek mythology, Agrius was a son of Parthaon, King of Calydon. Agrius' sons (including Melanippus and Thersites) overthrew his brother, Oeneus but were themselves overthrown by Diomedes, who reinstalled Oeneus as King.

Agrius was also a son of Odysseus by Circe and a brother of Latinus and Telegonus, mentioned only in Hesiod's Theogony (1011f).