Les Appalaches ( 'Municipalité régionale de comté des Appalaches') is a regional county municipality (RCM) in the Chaudière-Appalaches region in southeastern Quebec, Canada. It was established in 1982 from parts of the historic counties of Beauce, Frontenac, Mégantic, and Wolfe. The county seat and largest city is Thetford Mines.
The name of the RCM is linked to its location in the Appalachian Mountains with Mounts Adstock, Caribou, Oak, and Saint-Adrien being the highest. Until 2008, it was known as L'Amiante Regional County Municipality, because of the importance of asbestos mining in the region (amiante is French for "asbestos").