Altai (Mongolian: Алтай) is a sum (district) of Bayan-Ölgii Province in western Mongolia.

[1] Altai sum was established on February 12, 1959, by the Decree of the Presidium of the MPC of the Mongolian People's Republic.

[2] The centre of the district, Chikhertei, lies 115 kilometres (71 mi) west of Ölgii.

As of 2015 there were 120,650 livestock, consisting of 10,251 cattle, 57,106 sheep, 6,159 horses, 46,737 goats and 397 camels.

Electricity has been provided in Altai since 2001 thanks to the establishment of a 10 kW hydropower substation, though only 50% of households have sewerage.