Abstract: A ball coupler assembly for a gooseneck hitch is described for attachment to a truck having an upstanding coupler ball mounted thereon which extends upwardly from the bed of the truck. The hitch assembly of this invention is secured to the lower end of an adjustable jack at the forward end of the trailer or the like. The hitch comprises a support member having a ramp-like guide at the forward end thereof adapted to guide the coupler ball into coupling position. A coupler is mounted on the support member and extends upwardly therefrom and has an open lower end adapted to receive the coupler ball therein. A slide member is slidably mounted on the support member below the coupler opening and is movable between forward, intermediate and rearward positions. A locking mechanism is mounted on the support member and permits the slide to be moved rearwardly with respect to the hitch so that the coupler ball may be received within the coupling.