Fosteau Castle (French: Château du Fosteau) is a castle in Leers-et-Fosteau in the municipality of Thuin, province of Hainaut, Wallonia, Belgium.

The first castle at Fosteau was erected in the 14th century.

In approximately 1380 Wauthier de Semousies became owner when Duchess Joan of Brabant gave it to him.

Since 1980, it has housed an exhibition of antique furniture.

This article about a castle or château in Belgium is a stub.