Sayano-Shushenskoe Reservoir, Artificial reservoir in central Siberia, Russia.

The Sayano-Shushenskoe Reservoir is a 621 km² artificial lake on the Yenisei, impounded by a 242 m high arch-gravity dam. It stretches about 320 km: narrow and deep (up to 220 m) in the Sayan gorge, widening to 6–9 km and 8–30 m deep in the Tuva basin. Its level varies by up to 40 m annually.

The dam was built between the late 1960s and 1985 and was a major infrastructure project during the Soviet era. This construction marked a turning point in the economic development of central Siberia.

The reservoir's name combines the Sayan Mountains with the village of Shushenskoye, where Lenin was exiled from 1897 to 1900. Shushenskoye lies about 70 km downstream from the dam, a link Soviet planners considered symbolic. The reservoir is also one of 70 strategic drinking-water sources reserved for federal ownership.

The water is used to generate electricity through a large hydroelectric power station that supplies the surrounding areas. Visitors should expect cold water temperatures and watch for steady paths, especially when exploring the shoreline.

The reservoir borders the Sayano-Shushenski Nature Reserve, established in 1976 and a UNESCO biosphere reserve since 1985. Eleven rare bird species listed in Russia's Red Book occur here; the protected regime keeps stable numbers of golden eagle, saker falcon, peregrine falcon and osprey. The black stork once nested on Yenisei stretches in Tuva that the reservoir flooded, and is still seen there, though nesting is unconfirmed.