The Vanj River is a river in east Tajikistan. It is a right tributary of the Panj River in Vanj district, north-western Gorno-Badakhshan. It flows southwest between the Darvoz Range to the north and the Vanj Range to the south, joining the Panj at 38°18′N 71°20′E / 38.300°N 71.333°E. The Vanj valley is broader and more fertile than other valleys feeding the Panj. Vanj town is about 20 km upstream from the Panj. At the head of the valley, beyond the village of Po-i-Mazar, the river turns southeast (going upstream) and is fed by the Geographical Society Glacier near Independence Peak. Beyond the head of the valley are the Academy of Sciences Range and the Fedchenko Glacier.
South, on the other side of the Vanj Range, is the valley of the Yazgulyam River. The Vanji language, formerly spoken in the valley, is extinct.