Jaxartosaurus (jak-sahr-toh-sore-us ) was a herbivorous hadrosaur similar to Corythosaurus. Its fossils were found in China.

It had a large, helmet-like crest that it used to vocalize with members of the same herd. Females had the smallest crests, and juveniles had none at all. It was roughly 30 feet (9 metres) long; it was a lambeosaurine hadrosaurid, a duck-billed dinosaur. Fragmentary fossils (just the skull roof and braincase) were found near the Jaxartes River in Kazakhstan. This wide-headed plant-eater had flat-topped teeth. It lived during the late Cretaceous period, about 91-83 million years ago. Jaxartosaurus was named by Riabinin in 1939.