The term Wei may refer to:
* Northern Wei Dynasty, archaeologically the most famous of the Wei dynasties.
* Wei , state during the Spring and Autumn Period
* State of Wei during the Spring and Autumn Period and the Warring States Period
* Kingdom of Wei during the Three Kingdoms Period
* Wei Zhongxian, considered by many to be the most infamous eunuch in Chinese history. Orginal name was Li Jinzhong.
* Wei Jingsheng, a Chinese dissident
* Wei Qing, a general of the Western Han Dynasty
* Lady Wei Shuo, calligrapher
* Wei Yan, a military officer of Shu during the Three Kingdoms Period
* Shang Yang, Qin minister, originally known as Wei Yang
* Wei Zheng, a statesman of the Tang Dynasty
* , a Chinese volleyball player
* Wei Chen, a Canadian television and radio journalist
* Zhao Wei, a Chinese film actress and pop singer, sometimes referred to by her English name, Vicki Zhao
* a common misspelling of Michelle Wie, golfer
*Wei Hai, an ancient wargame
*Wei , a company-grade officer in Chinese armed forces.
* Wei River, a main tributary to the Yellow River]
* Wei, a star otherwise known as Epsilon Scorpii
The acronym WEI may also refer to:
* Wau Ecology Institute
* The Windows Experience Index reported by the Windows System Assessment Tool, a measure of the user-perceived performance of a computer running Microsoft Windows.