The red-bellied squirrel (Rubrisciurus rubriventer) is a species of squirrel. Until recently, it was described as a species in the genus Callosciurus, but since the 1990s it is generally placed in its own genus Rubrisciurus. It is endemic on the Indonesian island of Sulawesi. With a length of 25 cm (head and body), it is rather large for a squirrel. It lives in the tree tops of the rainforests of the island.