Bas-Vully (Arpitan: Bâs-Vulyi) is a former municipality in the district of See in the Canton of Fribourg in Switzerland . On 1 January 2016 the former municipalities of Bas-Vully and Haut-Vully merged to form Mont-Vully.

Bas-Vully is first mentioned in 968 as Williacense. Until 1831 it was known as vor Commune générale des quatre villages de La Rivière. The municipality was formerly known by its German name Unterwistenlach; however, that name is no longer used.

Bas-Vully had an area, as of 2009, of 10 square kilometers (3.9 sq mi).