The Château de Lassay is a 15th-century castle in Lassay-les-Châteaux, in the Mayenne department.

The first mention of a castrum in Lassay dates back to the 12th century.

Owned by Charles de Vendôme at the beginning of the 15th century, the castle was destroyed by French troops as Charles de Vendôme supported the English during the Hundred Years War.

In 1458, the French king Charles VII allowed the son of Charles de Vendôme, Jean II, to rebuild a castle.

The castle has been listed as a monument historique since 1862.