A folding roof comprises a flexible cover anchored at its rear to a frame in an opening in a motor vehicle roof. The front of the cover is mounted on a rigid plate carried by lifting brackets rockably engaged with a front cross member longitudinally slidable in the frame. Cam blocks at the front end of the frame are engaged by the lifting brackets so that when the front cross member is moved to a roof-closed position, the lifting brackets, and thus the plate, are urged downwardly by the cam blocks so as to seal the front of the cover with the vehicle roof.