Abstract: A folding portable tree step includes a channel-shape support leg pivotally mounted at a bottom portion to a channel-shape foot member so that when the two are folded for storage purposes, both channel members are open in the same direction. A special lag screw with a square head is pivotally and slidably mounted to an upper portion of the support arm, and a lag screw pivot pin slidably mounts the screw into cam-like guides provided in the channel legs of the support leg. When the lag screw extends outwardly from the support leg and the folded foot member, and the screw pivot pin is in the lower portion of the guide slot, the head of the lag screw is held by the web of the support leg channel so that the lag screw will not pivot when being initially driven into a tree. When the lag screw is moved longitudinally with respect to the support leg, the pivot pin moves the square screw head away from the support leg channel web, and the screw can be pivoted with respect to the support leg.