Vassieux-en-Vercors (French pronunciation: [vasjø ɑ̃ vɛʁkɔʁ], literally Vassieux in Vercors; Occitan: Vaciu de Vercòrs) is a commune in the department of Drôme in southeastern France.

The town is known for its assistance to the French Resistance during World War II, for which it was awarded the Ordre de la Libération.

The Plateau de Vassieux is the site of numerous other karst phenomena, such as limestone pavements and caves, which are studied and explored by local speleology groups.

Vassieux-en-Vercors is home to several prehistoric archaeological sites, and has a Museum of Prehistory which was created in May 1970 after the discovery of a flintknapping workshop.

A memorial was built at the Col de la Chau 44°54′27″N 5°21′40″E / 44.90760°N 5.36124°E / 44.90760; 5.36124 to remember the grim events of the Second World War, and includes a cemetery where the victims of a July 1944 German massacre are buried.