A dog step attachment attaches to a receiver hitch of a pickup truck to provide an intermediate step for assisting a dog in jumping into the bed of the pickup truck. The attachment includes a first frame member received in the receiver hitch, a second frame member pivotally connected to a rearward end of the first frame member, a third frame member connected to the second frame member, and a platform attached to and supported by the third frame member. The second frame member is movable relative to the first frame member between a folded down position for use as a dog step and a folded up position for transport. Springs are used to hold the second frame member in over-center conditions in the folded down and folded up positions. Adjustments are provided for accommodating different heights of receiver hitches and pickup beds.