Abstract: The invention is a lift for the gate of a truck, and especially a gate at the side of the truck. An L-shaped lift arm has base bars pivotally connected to an actuator mechanism beneath the bed of a truck. These arms swing to the side of the truck when extended and a lift bar on the base bars extends therefrom to engage the outside of a truck gate and the lift bar is angled from the base bars to push the gate upwardly to its closed position when the base bars are rotated to their extended position. The actuator mechanism includes two chain connected sprockets: a smaller sprocket at the base bar pivot and a larger sprocket connecting with the piston of a cylinder. The sprocket pitch diameter ratios are such that rotation of approximately 90.degree. by the larger sprocket will effect an 180.degree. rotation of the smaller sprocket, permitting the lift arm to swing from a fully retracted position underneath the body of the truck to a fully extended position where the lift bar closes the gate.