Ornitholestes is often portrayed as a fast, long-legged theropod, but its lower limb bones were fairly short. Osborn (1917) calculated that the shin bone was only about 70.6% as long as the thigh bone. The foot bones were spaced closely, but not fused together. As is typical of theropods, the feet were tridactyl (three-clawed). John H. Ostrom (1969) noted that the claw of digit II (the innermost toe) was larger than those of digits III and IV, and suggested that this digit may have borne a modified sickle claw similar to that of Deinonychus. However, as both Ostrom (1969) and Paul (1988) noted, the poor preservation of digit II makes this hypothesis difficult to confirm.
The name "Ornitholestes" means "bird robber." It comes from the Greek ὄρνις/ornithos meaning "bird" and λῃστήσ/lestes meaning "robber."