Duan may refer to:
- Duan (tribe), pre-state tribe during the era of Sixteen Kingdoms in China
- Dan rank mark of level in Japanese martial arts
- Lê Duẩn, the General Secretary of the Communist Party of Vietnam from 1959 until his death in 1986, and leader of Vietnam from 1969 to 1986
- Duan (surname) a Chinese surname
- Du'an Yao Autonomous County, in Guangxi, China
- Zaiyi, Prince Duan (1856-1922), Manchu prince and statesman during the late Qing dynasty
- Duan Qirui (1865 - 1936), Chinese politician
- "DUAN" a tag applied to the last post of the day at the sports blog Deadspin. The term is an acronym for "Deadspin Up All Night", and that post is often used as an open comments thread for readers visiting the site during evening and overnight hours in the US, when the site is not being updated.