Abstract: A wheel clamp assembly to be applied on a road wheel of a vehicle to prevent unauthorized operation of the vehicle. The assembly includes a first elongate arm member and a catch member at one end of the first arm member projecting transversely of the first arm member. The first arm member and a second elongate arm member are each joined at their bottom ends to an elongate body member. The body member supports the arm members in spaced apart relationship so that the width of the road wheel can be accommodated between the arm members. The second arm member is movable relative to the first arm member between an inoperative position spaced from the first arm member an amount sufficient to permit the catch member to be located into and out of the wheel well opening, and an operative position wherein the second arm member is substantially parallel to the first arm member and extends transversely of the front face of the wheel. A key-operated locking mechanism retains the second arm member in the operative position.