Abstract: A vertically disposed wheel chock for tandem wheels which engages the opposed tread surfaces of the tandem wheels. The wheel chock includes a pair of members which can be moved toward and away from each other and each member being wedge-shaped and including side plates with inclined edges for engagement with the opposed curved tread surface of pneumatic tires on the tandem wheels. The members are securely engaged with the tire tread surfaces above and below the rotational axes of the wheels to prevent the tandem wheels from rolling in relation to a support surface.