| Named By: | Pascal Godefroit, Yuri Bolotsky & Vladimir Alifanov in 2003 |
| Time Period: | Late Cretaceous, 72 Ma |
| Location: | Russia, Amur Region - Tsagayan Formation |
| Size: | Up to 12 meters long |
| Diet: | Herbivore |
| Fossil(s): | Almost complete specimen |
| Classification: | | Chordata | Reptilia | Dinosauria | Ornithischia | Ornithopoda | Hadrosauridae | Euhadrosauria | Lambeosaurinae | |
Olorotitan was a genus of lambeosaurine duckbilled dinosaur from the middle or latest Maastrichtian-age Late Cretaceous, whose remains were found in the Tsagayan Formation beds of Kundur, Amur Region, Far Eastern Russia. The type, and only species is Olorotitan arharensis whose holotype specimen, consisting of a nearly complete skeleton, was described by Pascal Godefroit et al. in mid-2003. The generic name Olorotitan means "gigantic swan", while the specific descriptor arharensis refers to the location of the fossil find at Arhara County. Olorotitan is distinct from other crested duckbills by its possession of an unusual crest that points backward and takes on a hatchet or fan-like shape. Its discovery has implications for the diversity of lambeosaurine hadrosaurids.