Abstract: A hydraulic actuator of a motor vehicle friction clutch comprises a cylinder and a piston defining between them a control chamber. The cylinder and piston are hollow, and mounted concentrically with respect to each other, with the cylinder surrounding the piston and abutting at its leading end on a bearing carried by the clutch cover plate, the cylinder having slots for preventing it from rotating with respect to a fixed part of the vehicle. The piston cooperates with the fixed ring of a rolling bearing of an actuating element which acts in traction on the declutching member of the clutch.