Kamuysaurus is a genus of herbivorous edmontosaurin saurolophine hadrosaurid dinosaur from Late Cretaceous Maastrichtian marine deposits of the Yezo Group (Hakobuchi Formation) in the Hobetsu area near the town of Mukawa, Hokkaido in Japan.

In 2019, the type species Kamuysaurus japonicus was named and described by Professor Yoshitsugu Kobayashi, Tomohiro Nishimura, Ryuji Takasaki, Kentaro Chiba, Anthony Ricardo Fiorillo, Kohei Tanaka, Tsogtbaatar Chinzorig, Tamaki Sato and Kazuhiko Sakurai.

The generic name is derived from kamuy, meaning "deity" in Ainu, the language of the original inhabitants of Hokkaido.

[1] The holotype, HMG-1219, has been found in a marine layer of the Hakobuchi Formation, part of the Yezo Group, dating from the early Maastrichtian, between 72.1 and 70.6 million years old.

It consists of a nearly complete skeleton with skull, only missing the snout, parts of the sacral vertebrae and phalanges.