Casteldelfino is a comune (municipality) in the Province of Cuneo in the Italian region Piedmont, located about 70 kilometres (43 mi) southwest of Turin and about 45 kilometres (28 mi) northwest of Cuneo.

Casteldelfino borders the following municipalities: Bellino, Elva, Oncino, Pontechianale, and Sampeyre. It is located in the upper Varaita Valley.