Wannanosaurus (meaning "Wannan lizard", named after the location where it was discovered) is a genus of basal pachycephalosaurian dinosaur from the Maastrichtian-aged (Upper Cretaceous) Xiaoyan Formation, about 70 million years ago, in what is now Anhui, China. The type species Wannanosaurus yansiensis was described by Hou Lian-Hai in 1977.