Yunnan (simplified Chinese: 云南; traditional Chinese: 雲南; pinyin: Yúnnán; IPA: [y̌nnǎn] ( listen)) is a province of the People's Republic of China, located in the far southwest of the country spanning approximately 394,000 square kilometers (152,000 sq mi) and with a population of 45.7 million (2009). The capital of the province is Kunming. The province borders Burma, Laos, and Vietnam.

Yunnan is situated in a mountainous area, with high elevations in the northwest and low elevations in the southeast. Most of the population lives in the eastern part of the province. In the west, the relative height from mountain peaks to river valleys can be as much as 3,000 m. Yunnan is rich in natural resources and has the largest diversity of plant life in China. Of the approximately 30,000 species of higher plants in China, Yunnan has perhaps 17,000 or more. Yunnan's reserves of aluminium, lead, zinc and tin are the largest in China, and there are also major reserves of copper and nickel. Yunnan has over 600 rivers and lakes, which provide an annual water supply of 222 billion cubic meters. Projected hydropower reserves stand at 103 GW, with an exploitable capacity of 90 GW.