| Named By: | Halszka Osmolska, Ewa Roniewics & Rinchen Barsbold in 1972 |
| Time Period: | Late Cretaceous, 70 Ma |
| Location: | Mongolia - Nemegt Formation |
| Size: | Largest specimens up to 8 meters long |
| Diet: | Uncertain but possible omnivore |
| Fossil(s): | Numerous individuals including juveniles |
| Classification: | | Chordata | Reptilia | Dinosauria | Saurischia | Theropoda | Ornithomimidae | |
Gallimimus ( GAL-i-MY-mas; meaning "chicken mimic") is a genus of ornithomimid theropod dinosaurs from the late Cretaceous period (Maastrichtian stage) Nemegt Formation of Mongolia. With individuals as long as 8 m (26 ft), it was one of the largest ornithomimosaurs. Gallimimus is known from multiple individuals, ranging from juvenile (about 0.5 m tall at the hip) to adult (about 2 m tall at the hip). The type species is G.bullatus, which means "capsuled chicken mimic".