Storage unit mounting apparatus removably and lockably attachable to a vehicle is provided. The apparatus includes a single, cantilevered support member removably and irrotationally attachable at its proximal end to the vehicle, the distal end of the support member supporting a receiver having integral mounting means to which the storage unit is attachable. The apparatus is especially suited for vehicles such as motorcycles, all-terrain-vehicles (ATVs), bicycles and the like.