The Ondava is a 146.5 km long river in Slovakia, the northern source river of the Bodrog. Its source is in the Low Beskids (Eastern Carpathian Mountains), near the village Nižná Polianka, close to the border with Poland. The Ondava flows south through the towns Svidník, Stropkov and Trhovište, and through the Ondavská Highlands.
Near the village Cejkov, the Ondava joins the Latorica and forms the Bodrog river, itself a tributary of the Tisza. The Ondava river is 44% regulated.