Guern (; ) is a commune in the Morbihan department of Brittany in north-western France.
Inhabitants of Guern are called in French Guernates.
The village centre is located southwest of Pontivy. The Sarre river flows through the village. The main settlements are the village centre, Quelven and Locmeltro. In the village of Quelven is the basilica Notre-Dame de Quelven.