Rostislav III Mstislavich of Kiev

Rostislav Mstislavich (born 1189; died in or after 1240/1249) was a Smolensk Rurikid, son of Mstislav Davidovich and ancestor of the later Smolensk princely line. He took the Smolensk throne after his father's death in 1230 but was expelled in 1232 by his cousin Sviatoslav Mstislavich with an army of Polotsk princes.

He may be the Rostislav who entered Kiev in 1239 during the Mongol invasion, after Mikhail Vsevolodovich fled to Hungary, and claimed the grand-princely title. Daniel of Galicia soon drove the claimant out and installed his voivode Dmytro there. Rostislav's sons Gleb, Mikhail and Fyodor the Black later all ruled Smolensk.