Coity Castle (Welsh: Castell Coety) in Glamorgan, Wales, is a Norman castle built by Sir Payn "the Demon" de Turberville (fl. 1126), one of the legendary Twelve Knights of Glamorgan supposed to have conquered Glamorgan under the leadership of Robert FitzHamon (d. 1107), Lord of Gloucester. Now in ruins, it stands in the community of Coity Higher near the town of Bridgend, in the County Borough of Bridgend. Very close to the castle is the battlemented parish church of St Mary the Virgin, dating from the 14th century.
The castle began as a late 11th-century ringwork. A rectangular stone keep and the main curtain wall were added by the Normans in the 12th century, under the de Turberville family. The three-storey keep was primarily a defensive structure.
Extensive reworking took place in the 14th century, when a domestic range was attached to the keep by the middle gatehouse. New stone vaults replaced the earlier timber floors. The central octagonal pier for the vaults is still prominent among the castle ruins. An adjoining chapel wing with a tall east window was added to the first floor at the eastern end of the domestic range in the 15th century.