Malguénac (French pronunciation: [malɡenak]; Breton: Malgeneg) is a commune in the Morbihan department of Brittany in north-western France.

Malguénac is border by Cléguérec to the north, by Séglien to the west, by Guern to the south and by Pontivy and Le Sourn to the east.

Inhabitants of Malguénac are called in French Malguénacois.

After having declined for a long time, the population of the municipality has been increasing steadily since 1975.

An epidemic of plague caused several deaths between March and October 1598 in the parish.