Achit Lake (UK: /ˈætʃɪt/, US: /ˈɑːtʃɪt/; Mongolian: Ачит нуур Mongolian pronunciation: [ˈatɕʰɪtʰ nʊːr]) is a freshwater lake in Bayan-Ölgii Province and Uvs Province, Mongolia, in the west of the country.

At an elevation of 1,435 m above sea level it covers an area of 290 km2.

The coast is covered with steppes, mostly hilly but swampy on the northwest and northeast.

Several rivers flow into the lake.

This article related to a lake in Mongolia is a stub.