The Styr (Ukrainian: Стир; Belarusian: Стыр; Russian: Стырь) is a right tributary of the Pripyat, with a length of 494 kilometres (307 mi).

Its basin area is 13,100 square kilometres (5,100 sq mi) and located in the historical region of Volhynia.

During the Khmelnytskyi Uprising, the Battle of Berestechko took place in 1651 on the river between armies of the Polish-Lithuanian Commonwealth and the Cossacks of Bohdan Khmelnytsky.

[4] During 1915–1916, the Styr river was the front line between the Austro-Hungarian and Imperial Russian armies.

[5][6] The river was also a barrier to the German invasion on June 22, 1941, during Operation Barbarossa on the South-Western Front.