The Anabar River is a river in Sakha, Russia, located just west of the Lena River. Its catchment extends into the Putoran Mountains that form the highest part of the Central Siberian Plateau.

Its mean annual discharge is approximately 700 cubic metres per second, concentrated heavily in early summer when the ice that covers the river for most of the year thaws. The Gulf of Anabar is believed to be the easternmost fjord in Russia - defining the point at which the climate during the Last Glacial Maximum became too dry for glaciers to form - one notices a quite clear transition from fjords to deltas at river mouths when the Lena River delta is reached shortly to the east.

The basin of the Anabar river is notable as the location of the largest concentration of diamond deposits in the world outisde of Africa and Australia. These deposits made the Soviet Union into one of the world's largest producers of diamonds, and remain the economic mainstay of the area.