| Named By: | Henry Fairfield Osborn in 1903 |
| Time Period: | Late Jurassic, 154 Ma |
| Location: | USA - Morrison Formation |
| Size: | Estimated at 2 meters long, possibly slightly larger |
| Diet: | Carnivore |
| Fossil(s): | Skull and partial post cranial skeleton |
| Classification: | | Chordata | Reptilia | Dinosauria | Saurischia | Theropoda | Maniraptora | Ornitholestinae | |
Ornitholestes (meaning "bird robber") is a small theropod dinosaur of the late Jurassic (Brushy Basin Member of the Morrison Formation, middle Kimmeridgian age, about 154 million years ago) of Western Laurasia (the area that was to become North America).
To date, Ornitholestes is known only from a single partial skeleton with a badly crushed skull found at the Bone Cabin Quarry near Medicine Bow, Wyoming, in 1900. It was described by Henry Fairfield Osborn in 1903. An incomplete hand was later attributed to Ornitholestes, although it now appears to belong to Tanycolagreus. The type (and only known) species is O. hermanni. The specific name honors the American Museum of Natural History preparator Adam Hermann.