Gigantoraptor is a genus of giant oviraptorosaurian theropod dinosaur. It was discovered in 2005 in the Iren Dabasu Formation, Erlian basin, in Inner Mongolia. The age of the Iren Dabasu formation is controversial. Based on ostracods, Godefroit suggested the unit was Nemegt equivalent or about 70 million years old, although some dinosaur remains suggest an older Baynshirenian age c 85-90 Ma.