The Kolyma River (Колыма́) is a river in northeastern Siberia, whose basin covers parts of the Republic of Sakha, Chukotka, and Magadan oblast.

The Kolyma is 2129 km long and drains a basin of 679,934 square kilometres (262,209 square miles), making it the sixth largest watershed in Russia. The Kolyma watershed consists of extensive mountains in the south and east, rising to 2998 metres (8799 feet) at Mount Chen in the Cherskii Range, and of the vast Kolyma Plain in the north where the river empties into the East Siberian Sea. Its mean discharge of 4060 cubic metres per second (143,400 cubic feet per second) is also the sixth largest in Russia after the Yenisei, Lena, Ob, Amur and Volga.

The Kolyma is frozen to depths of several metres for about 250 days each year, becoming free of ice only in early June, and freezing up again by early October.

The Kolyma basin is best-known for its Gulag slave labour camps and gold mining, both of which have been extensively documented since Stalin era Soviet archives opened.