Robert L. Jaffe (born May 23, 1946) is an American physicist and the Jane and Otto Morningstar Professor of Physics at the Massachusetts Institute of Technology (MIT). He was formerly director of the MIT Center for Theoretical Physics.
Jaffe was born in Bath, Maine, USA, in 1946 and educated in public schools in Stamford, Connecticut. He received his A.B. degree in physics, summa cum laude, from Princeton University, where he was valedictorian of the Class of 1968. He received his M.S. and Ph.D. degrees from Stanford University in 1971 and 1972, respectively. At Stanford he founded the Stanford Workshops on Political and Social Issues.
In 1972, Jaffe moved to MIT as a postdoctoral research associate in the Center for Theoretical Physics; he joined the faculty in 1974. From 1975 until 1979, he was an Alfred P. Sloan Foundation Research Fellow. Jaffe has spent sabbatical years at the Stanford Linear Accelerator Center (1976), Oxford University and the European Organization for Nuclear Research (CERN) (1978–79), Boston University (1986–87), and at Harvard University (1996–97). He has served on the program advisory committees of several national laboratories including the Stanford Linear Accelerator Center and Brookhaven National Laboratory. For a decade he chaired the advisory council of the physics department of Princeton University. Since 1996, Jaffe has been an advisor to and Visiting Scientist at the RIKEN-Brookhaven Research Center. He spent the fall term of 1997 on leave from MIT at the RIKEN-Brookhaven Center.