Questembert (Breton: Kistreberzh) is a commune in the Morbihan department in Brittany in north-western France.
It is located approximately 25 km (16 mi) from Vannes.
Inhabitants of Questembert are called Questembertois. It was 7,404 as of the estimation of 2005.
In 2008, there 3.61% of local children attended bilingual schools in primary education, learning partly in Breton.