Omeisaurus (oh-mee-sore-us) was a sauropod dinosaur from the Late Jurassic Period of what is now China. Its name comes from Mount Emei, where it was discovered. Like other sauropods, the Omeisaurus is herbivorous and large. It measured 10 to 15 metres (30 to 45 feet long and 4 metres (12 feet) high and weighed 4 tons.

It had the typical bulky body and long neck of other dinosaurs in its suborder. Unlike many sauropods, however, its nostrils were located close to the end of its nose. The back of the Omeisaurus was higher at its hips than at its shoulders.