Achit Lake (/ˈætʃɪt/; Mongolian: Ачит нуур [átɕʰɪtʰ nʊ́ːr]) 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. It is 28 km long, 16 km wide, and 10 m deep. The coast is covered with steppes, mostly hilly but swampy on the northwest and northeast. Several rivers flow into the lake.

• Ramsar sites in Mongolia

• The Annotated Ramsar List: Mongolia
• Big Soviet Encyclopaedia – Russian (АЧИТ-НУР)
• Limnological Catalog of Mongolian Lakes