This article refers to the clamp used to hold together two workpieces. For clamps used to secure stage lighting instruments to battens, see C-Clamp (stagecraft). For the Chicago Indie Rock band, see C-Clamp

A C-clamp or G-clamp is a type of clamp device typically used to hold a wood or metal workpiece, and often used in, but are not limited to, carpentry and welding. These clamps are called "C" clamps because of their C shaped frame, but are otherwise often called G-clamps or G-cramps because including the screw part they are shaped like an uppercase letter G.