Tsai Duei (; born 1 December 1947) is a Taiwanese electrical engineer who served as the Minister of Transportation and Communications.
Tsai graduated from National Taipei University of Technology in 1968 with a bachelor's degree in electrical engineering. He then earned a master's degree in electronic engineering from National Taiwan University (NTU) in 1983 and earned his Ph.D. from NTU in electrical engineering in 1987.