Abstract: A self-erecting step stool comprising a top, pivoted leg structures at the ends of the top, a pivoted leg holding strut between the legs and having positive engagement therewith when the legs are extended; a strengthening rib secured or integral to the top at the underside thereof, said pivoted strut being pivoted in journals which are secured to said strengthening rib whereby sidewise thrust on the leg structures at the ends of the step stool is transferred through the pivoted strut to the strengthening rib and thence to the top.