Abstract: A flexible sun roof for cars, comprising a frame movable fowardly and rearwardly in a rectangular roof opening in the car, a flexible cover connected at one end to the frame and at its other end to the rear edge of the opening. The cover is stretched in its closed position over the opening and folded rearwardly in the open position. A device for driving the frame forwardly or rearwardly for engaging it against the front edge of the said opening, and for blocking it at least in said forward position is provided. The device has a support on which the frame is mounted.