The Diois Mountains (French: Massif du Diois, pronounced [masif dy diwa]) are a massif of the French Prealps located in the department of Drôme and in the extreme south of the department of Isère.

Similar to the Baronnies massif, the Diois region is characterized by mid-altitude limestone mountains, a rock type also abundantly found in the Vercors.

The small valleys, sometimes carved into gorges by watercourses, are oriented in various directions, creating a highly compartmentalized terrain.

Along rivers and streams, signs of Eurasian beavers and European otters can be observed, with occasional sightings of these animals.

The dry slopes of Jocou and certain summits in the Diois still host a few pairs of rock partridges.