Abstract: A self-unloading forage wagon of the type in which the floor of the box of the wagon is thirty to forty inches from the ground with the rear of the wagon closed by a single tailgate hinged at the bottom to the box and which extends above the opening at the back of the wagon. Apron unloading chains in the bottom of the box of the wagon which are driven rearwardly by a source of power in turn effect a drive of unloader chains rearwardly on the tailgate to discharge a load of material such as hay, corn or the like from the wagon when the tailgate is lowered so that rear or upper end is in engagement with the ground.