The Kunlun Mountains (simplified Chinese: 昆仑山; traditional Chinese: 崑崙山; pinyin: Kūnlún Shān, pronounced [kʰu̯ə́nlu̯ə̌n ʂán]; Mongolian: Хөндлөн Уулс) are one of the longest mountain chains in Asia, extending more than 3,000 km. In the broadest sense, it forms the northern edge of the Tibetan Plateau south of the Tarim Basin and the Gansu Corridor and continues east south of the Wei River to end at the North China Plain.

The exact definition of this range seems to vary. An old source uses Kunlun to mean the mountain belt that runs across the center of China, that is, Kunlun in the narrow sense, Altyn Tagh, Qilian Mountains and Qin Mountains. A recent source has the Kunlun forming most of the south side of the Tarim Basin and then continuing east south of the Altyn Tagh. Sima Qian (Shiji, scroll 123) says that Emperor Wu of Han sent men to find the source of the Yellow River and gave the name Kunlun to the mountains at its source. The name seems to have originated as a semi-mythical location in the Shan Hai Jing.