The Tian Shan (Chinese: 天山; pinyin: Tiān Shān; literally "celestial mountains"; Mongolian: Тэнгэр уул; Uyghur: تەڭرى تاغ‎, ULY: Tengri Tagh), also spelled Tien Shan, is a large mountain system located in Central Asia. The highest peak in the Tian Shan is Victory Peak (Jengish Chokusu), 7,439 metres (24,406 ft).

The Chinese name for Tian Shan may be derived from the Xiongnu name qilian (祁连), which was described by the Shiji as the homeland of the Yuezhi, and has been said to refer to the Tian Shan rather than to the range 1,500 kilometres (930 mi) further east now known by this name. The nearby Tannu-Ola Mountains (Tuvan: Таңды-Уула Tangdy-Uula) bear the same name ("heaven/celestial mountains" or "god/spirit mountains").