Blonay Castle, Castle in Blonay, canton Vaud, Switzerland

Blonay Castle is a castle in the municipality of Blonay, canton Vaud, Switzerland. Its oldest part is a sturdy square keep, with only two of four towers remaining around an irregular rectangular plan. A forecourt on the western edge has a Renaissance-style loggia from 1677, and the 15th-century chapel contains stained glass windows from 1577.

The castle was built in 1175 by William II of Blonay, a ministerialis in Savoy, on the site of a fortified structure documented in 1095. The Blonay family, enfeoffed to the counts of Savoy, enlarged it over generations with a keep, a curtain wall, a residence and a private chapel. Weakened after the Protestant Reformation and the Bernese invasion, the family sold the castle in 1752 to Richard de Graffenried and left for Vevey; the Blonays bought it back in 1806.

The castle's name comes from the Blonay family, whose seat it has been since the 12th century apart from a 1752–1806 interruption, when the Graffenrieds owned it. In 1772 the painter Gottfried Locher signed and dated a painted ceiling made for the Graffenrieds. The 15th-century chapel keeps stained glass windows dated 1577.

The fortress stands at 644 meters elevation and is maintained by the Blonay Foundation as a protected heritage site. Wear sturdy shoes when walking the grounds, as the paths are historic and uneven in places.

French painter Gustave Courbet painted the castle in 1875 while in exile in Switzerland, but he hid another artwork beneath the surface. This technique turned the fortress into a secret layer of artistic expression that few people knew about.