Horng-Tzer Yau (姚鴻澤) is a Taiwanese-American mathematician. Born 1959 in Taiwan, he received his B.Sc. in 1981 from National Taiwan University and his Ph.D. in 1987 from Princeton University. He joined the faculty of NYU in 1988, and became a full professor at its Courant Institute of Mathematical Sciences in 1994. He moved to Stanford in 2003, and then to Harvard University in 2005. He has also been a member of the Institute for Advanced Study in Princeton, New Jersey, in 1987-88, 1991–92, and 2003.
According to William C. Kirby, dean of the Faculty of Arts and Sciences at Harvard, "Professor Yau is a leader in the fields of mathematical physics, ... who has introduced important tools and concepts to study probability, stochastic processes, nonequilibrium statistical physics, and quantum dynamics."
- Simons Investigator Award 
- Sloan Foundation Fellowship
- Packard Foundation Fellowship, 1991
- Henri Poincaré Prize, 2000
- MacArthur Fellowship, 2000
- Morningside Gold Medal of Mathematics, 2001 
- Academician of the Academia Sinica
- Member of the American Academy of Arts and Sciences
- Member of the National Academy of Sciences 
- Fellow of the American Mathematical Society, 2012
- Editorial boards of Communications in Mathematical Physics, Cambridge Journal of Mathematics, Journal of Statistical Mathematics, Asian Journal of Mathematics, and Communications on Pure and Applied Mathematics