(Mongolian: Өгий нуур) is a freshwater lake in eastern Arkhangai, in central Mongolia.
The lake, designated as a Ramsar Site of International Importance, is known for its fish and for birdlife. It is a stopover point for migrating waterbirds of the family Anatidae. Almost half the lake is less than 3 m deep. There are several ger tourist camps around the lake, as well an information and training center.