Yuan Tseh Lee (; born 19 November 1936) is a Taiwanese chemist. He is a Professor Emeritus at the University of California, Berkeley. He was the first Taiwanese Nobel Prize laureate who, along with the Hungarian-Canadian John C. Polanyi and American Dudley R. Herschbach, won the Nobel Prize in Chemistry in 1986 "for their contributions to the dynamics of chemical elementary processes".
Lee's particular physical chemistry work was related to the use of advanced chemical kinetics techniques to investigate and manipulate the behavior of chemical reactions using crossed molecular beams. From 15 January 1994 to 19 October 2006, Lee served as the President of the Academia Sinica of Taiwan. In 2011, he was elected head of the International Council for Science.