Iskanderkul is a mountain lake of glacial origin in Tajikistan's Sughd Province.
It lies at an altitude of 2,195 metres (7,201 ft) on the northern slopes of the Gissar Range in the Fann Mountains. Triangular in shape, it has a surface area of 3.4 square kilometres (1.3 sq mi) and is up to 72 metres (236 ft) deep. Formed by a landslide that blocks the Saratogh river, the outflow of the lake is called the Iskander Darya, which joins the Yaghnob River to form the Fan Darya, a major left tributary of the Zeravshan River.