The Vilyuy River is a tributary of the Lena in eastern Siberia. The river is approximately 2,650 km long, of which around 1,450 km is navigable.

The Vilyuy's source lies near Ekonda, in the north of the Central Siberian Plateau. It then flows south east, through a lake and the towns of Cherynshevskiy, Suntar, Nyurba and Verkhnevilyuysk before joining the Lena near Sangar.

The river is known for the diamond mines established along it since the 1950s.