Sarzeau (French pronunciation: [saʁzo]; Breton: Sarzhav) is a commune in the Morbihan department of Brittany in north-western France.

Prehistoric monuments remaining include the menhirs of Kermaillard and Largueven, as well as the dolmens of Kergillet and Brillac.

The castle was a favorite spot of the Dukes of Brittany who often came for the hunting in the surrounding region [2].

During the Middle Ages, because of its size the town was divided into seven local divisions, a situation that still exists to some extent.

Sarzeau was the birthplace of Alain-René Lesage (1668–1747), the author of novel The Devil upon Two Sticks (1707), his comedy Turcaret (1709) and his picaresque novel Gil Blas, (1715–1735).