Abstract: A self-locking trailer hitch has a frame arranged for attachment to a vehicle, a housing arranged to slide longtudinally on the frame between extended and retracted positions, a swing bar pivotally attached to the housing to swing laterally about a vertical axis so that a hitch ball on the free end of the swing bar can be moved about for coupling of two vehicles. The swing bar, housing and frame have holes that will align when the swing bar is centered and the housing is extended, and a spring loaded pin that will lock the three holes and, hence, the related parts into extended and centered position when the towing vehicle is driven forward after coupling.