The Opava (, , ) is a river in the north-eastern Czech Republic, a left tributary of the Oder river. It originates at the confluence of Bílá (White), Strední (Middle) and Cerná (Black) Opava in Vrbno pod Pradedem and runs over 119 km (74 mi) to the Oder at Ostrava, with some 25 km (16 mi) forming the border with Poland.