The Uy River (Russian: Уй, Bashkir: Уй) is a river in Chelyabinsk Oblast in Russia with its upper reaches in Bashkiria. It partially flows along the borders of Chelyabinsk and Kurgan Oblasts with Kazakhstan. The Uy is a left tributary of the Tobol River. The length of the river is 462 km. The area of its basin is 34,400 km². It freezes up in November and stays icebound in April.