Abstract: A theft deterent device for vehicle covers to resist unauthorized removal of the cover from the vehicle in which the cover material has attached thereto one end of an elongated flexible member of high tensile strength, the free end of said flexible member having an enlargement with a dimension greater than the space between the peripheral edges of a closure member in such a door and the frame or body portion of the vehicle defining the opening for the closure member. The flexible member has a length to extend from the exterior surface of the vehicle through such space into the interior of the vehicle. When the closure member is closed and locked with the flexible member extending from the car cover through the peripheral space into the interior of the vehicle, the enlarged end resists withdrawal of the flexible member through said space and resists removal of the car cover.