Abstract: The lock mechanism for a fifth wheel hitch of the present invention includes a housing mounted on a pedestal, the housing having a hitch plate mounted on the upper end thereof. The hitch plate slot, for receiving a trailer pin, is mounted over a channel extending forwardly in the housing, such that the trailer pin will extend downwardly into the channel and slide along the channel bottom and between the channel side walls. A hook member is pivotally mounted on the housing and selectively projects through an opening in one side wall of the channel such that a hook arm retains the trailer pin in position in the channel. A handle mounted on the hook member to manually move the hook member between the engaged and disengaged positions. A lock plate is pivotally mounted to the housing and includes a throat with a first catch for retaining the handle in the disengaged position, and a second catch for retaining the handle in the engaged position.