Abstract: A locking device for a valve disposed in a housing including a stem assembly projecting from the valve for rotation of the valve between an open and closed position which includes a handle assembly provided with a handgrip portion at a first end thereof and a securing member at a second end thereof connected to the stem assembly. The locking device also provides for an abutment member mounted on the housing as well as a locking member mounted on the handle assembly so as to interfittingly cooperate with the handle assembly securing member and the abutment member to secure the valve in either the open or the closed valve position.