Gardiki Castle (Greek: Κάστρο Γαρδικίου) is a 13th-century Byzantine castle on the southwestern coast of Corfu. It is the only surviving medieval fortress on the southern part of the island. It was built by a ruler of the Despotate of Epirus,and was one of three castles which defended the island before the Venetian era (1401–1797). The three castles formed a defensive triangle, with Gardiki guarding the island’s south, Kassiopi Castle the northeast and Angelokastro the northwest.