Alex Tsai (Chinese: 蔡正元; pinyin: Cài Zhèngyuán; born 25 December 1953) is a Taiwanese politician and a member of the Kuomintang. He served as a legislator from 2008 to 2016. Tsai graduated from the and the John F. Kennedy School of Government of Harvard University. He was one of the 3rd members of the National Assembly.