Abstract: A convertible trailer and hitch-mountable platform apparatus has a platform assembly with removable wheel and tow bar assemblies. The platform is equipped with structure for mounting the disengaged tow bar in a transverse orientation to provide structural support when mounted on the receiver hitch of a vehicle for use as a utility platform. The tow bar includes a longitudinal tongue which is received in a transversely centered longitudinal member for a trailer configuration or a longitudinally centered cross member for a platform configuration. One end of the transversely assembled tow bar is mountable on the vehicle hitch receiver for supporting the utility platform and wheels in a generally horizontal position. The platform also includes structure for stowing the wheel assemblies. Each wheel assembly includes an axle assembly that is positionable to shift the wheels 90° upwardly and rearwardly for lowering the trailer deck for towing use behind a lawn tractor, mower or the like.