Chagytai Lake, Protected lake in Tandinsky District, Russia.

Chagytai Lake is a protected body of water in Tandinsky District, located in the Tuva Republic. The water features rocky and sandy shorelines alongside marshy zones where purple willows grow in the wetland areas.

In 1965 carp from Khakassia and bream from Novosibirsk Oblast were introduced, followed in 1966 by peled larvae flown in from Leningrad Oblast; peled thrived and commercial fishing began four years later. On 17 July 1995 the Chagytai biogydrogical zakaznik, covering 5,350 hectares, was created around the lake. In 1994 President Boris Yeltsin visited the lake.

The name Chagytai is thought to come from the Mongolian word Zagastan, meaning "place of fish". A Tuvan tradition holds that the body of one of Genghis Khan's sons was buried at the bottom of the lake. Tuvan herders have long lived around the water, and the lake now supports a commercial fishery.

Access is via a turnoff from the M54 Yenisey federal highway before Balgazyn village, about 70 km south of Kyzyl. The shoreline stretches nearly 20 km, with mostly gentle banks that become marshy and low in the southeast. Dust storms on the lake have caused fatalities, so check weather before setting out.

The lake drains through a single small river, the Mazhalyk, which joins the Soy and reaches the Maly Yenisei basin. Because of this outflow, peled and bream introduced here spread downstream into the Upper Yenisei, where they had been absent before the Sayano-Shushenskoye reservoir flooded the Sayan canyon.