Mstislav I Vladimirovich the Great (June 1, 1076, Turov – April 14, 1132, Kiev) is the Grand Prince of Kiev (1125–1132), the eldest son of Vladimir II Monomakh by Gytha of Wessex.

He figures prominently in the Norse Sagas under the name Harald, taken to allude to his grandfather, Harold II of England.

Mstislav's Christian name is Theodore.