Bayan-Ovoo (Mongolian: Баян-Овоо, Rich ovoo) is a sum (district) of Ömnögovi Province in the Gobi Desert of southern Mongolia.

[1] The sum is located in the Gobi Desert of southern Mongolia, 170 kilometres (110 mi) by road southwest of the provincial capital of Dalanzadgad,[2] at an elevation ranging from 2200 to 2700 metres above sea level.

It borders China to the south and the sums of Nomgon, Khankhongor, Tsogttsetsii, Manlai and Khanbogd in the northeast.

[1] The climate is generally warm, with little snow in the winter, and it is rare for it to rain during the summer months, with only 63.2-70.9 mm of precipitation falling annually.

[3] Although technically in a cold desert climate, the district has sufficient precipitation to support sparse plant life, particularly xerophytes (species adapted to low moisture levels) in low-lying areas.