The Osum is a river in southern Albania, one of the source rivers of the Seman. Its source is in the southern part of the Korçë District, near the village Vithkuq at an altitude of 1,050 metres (3,440 ft).
It flows initially south to the Kolonjë District, then west to Çepan, and northwest through Çorovodë where it flows through the famous Osum Canyon, Poliçan, Berat and Urë Vajgurore. It joins the Devoll near Kuçovë, to form the Seman. The discharge of the river is reported to vary between 5.11 m3 (180 cu ft)/s and 74.11 m3 (2,617 cu ft)/s.