Kassiopi Castle, Byzantine castle in Kassiopi, Greece.

Kassiopi Castle is a Byzantine fortress on the northeastern coast of Corfu featuring nineteen defensive towers in varied shapes. The structure combines circular and rectangular bastions to form an integrated defensive system.

Kassiopi Castle was one of three Byzantine-period castles defending Corfu before the Venetian era, forming a defensive triangle with Gardiki in the south and Angelokastro in the northwest. Excavated coins of emperors Maurice (582–602) and Basil II (976–1025) and 4th–7th century pottery suggest a Byzantine fort here by the 6th century. Count Bohemund of Taranto took it in 1081; Alexios I Komnenos recovered it in 1084 after three naval battles in the Corfu Channel. The Angevins held it from 1267, and the Venetians took it in 1386, then dismantled it.

Local lore tells of fire-breathing dragons that destroyed the castle and poisoned the village, a tale traced to the impression gunpowder explosions made on residents unfamiliar with such warfare. The story arose about a century after the Venetians dismantled the fortress in 1386.

The entrance is on the southeast side and leads to the partially preserved walls and towers of the site. Visitors should expect uneven ground and limited shade, particularly on sunny days.

The castle's interior, 35,177 m² within a 1.073 km perimeter, holds no buildings at all, only olive trees. The central tower has vanished, but the main gate still stands between two strong two-storey towers, its wall 1.9 m thick.