Liangshan Yi Autonomous Prefecture^{[lower-alpha 1]} is an autonomous prefecture occupying much of the southern extremity of Sichuan province, People's Republic of China. Its seat is Xichang. Liangshan covers an area of 60,261 km² (23,267 sq mi) and has over 4.8 million inhabitants as of 2020.^[1] It has the largest population of ethnic Yi (or Nosu) among China's prefectures. Liangshan contains a number of isolated villages high up on its cliffs, often known as "cliff villages".^[3]

Xichang has the Xichang Qingshan Airport and the Xichang Satellite Launch Center. The prefecture also features a substantial network of railways for both passengers and freight.

The Anning River, which runs into the Jinsha River (Yangtze River headwaters), is the main river in the area.

Owing to its low latitude and high elevation, Liangshan has a mild climate. Under the Köppen system, the prefecture belongs to the humid subtropical zone (Köppen Cwa). Winters feature mild days and cool nights, while summers are very warm and humid. Monthly daily mean temperatures range from 9.6 °C (49.3 °F) in January to 22.3 °C (72.1 °F) in July. Unlike much of the province, which lies in the Sichuan Basin, humidity levels in winter are rather low, but like the rest of the province, rainfall is concentrated in the months of June through September, and the prefecture is virtually rainless in winter.

Liangshan directly controls two county-level cities, 14 counties, and 1 autonomous county.

• Asteroid 121001 Liangshanxichang