The Salween River (; ; also spelled Salwine) rises in Tibet, after which it flows through Yunnan, where it is known as the Nujiang river (), although either name can be used for the whole river. The river is 2815 km long. It then leaves China and meanders through Myanmar (where it is known as the Thanlwin) and Thailand on its way to emptying in the Andaman Sea by Mawlamyine (Moulmien).

For most of its route the river is of little commercial value, and it passes through deep gorges and is often called China's Grand Canyon. It is home to over 7,000 species of plants and 80 rare or endangered animals and fish. Unesco said this region "may be the most biologically diverse temperate ecosystem in the world" and designated it a World Heritage Site in 2003.

The Nu people (Chinese: 怒族; pinyin: nù zú), one of the 56 ethnic groups officially recognized by the People's Republic of China, are named after this river.