Janq'u Uma, Mountain summit in La Paz Department, Bolivia.

Janq'u Uma is a 6,427 m mountain in the Cordillera Real of the Andes, in Larecaja Province, La Paz Department, Bolivia. It lies just south of the slightly lower Illampu, near Sorata, and together they form a single massif covering about 200 km², the largest glacial mass in Bolivia. The peak has a gentler profile and less local relief than Illampu.

The first ascent of Janq'u Uma was made in 1919 by the German climbers Rudolf Dienst and Adolf Schulze. Their route up the southwest face remains the easiest line on the mountain, rated PD, and later routes were opened on the northwest ridge and the west face.

The name Janq'u Uma comes from Aymara: janq'u means white and uma means water, so it is commonly rendered as "white water". Spanish sources also record the mountain as Ancohuma, and the peak appears under spellings such as Jankho Uma and Jankhouma. It stands near Sorata, in the Larecaja province of the La Paz Department.

The easiest route, still rated PD (not very difficult), climbs the southwest face; other lines follow the northwest ridge and the west face. Approach from the west or the northeast, each taking two to three days from Sorata. The peak lies just south of Illampu, near Sorata in the northern Cordillera Real.

Ancohuma and the slightly lower Illampu form a single massif of about 200 km², the largest glacier mass in Bolivia. The peak is visible from much of the road between La Paz and Lake Titicaca.