James P. Crutchfield (born 1955) is an American mathematician and physicist. He received his B.A. summa cum laude in physics and mathematics from the University of California, Santa Cruz, in 1979 and his Ph.D. in physics there in 1983. He is currently a professor of physics at the University of California, Davis, where he is director of the Complexity Sciences Center—a new research and graduate program in complex systems. Prior to this, he was research professor at the Santa Fe Institute for many years, where he ran the Dynamics of Learning Group and SFI's Network Dynamics Program. From 1985 to 1997, he was a research physicist in the physics department at the University of California, Berkeley. He has been a visiting research professor at the Sloan Center for Theoretical Neurobiology, University of California, San Francisco; a postdoctoral fellow of the Miller Institute for Basic Research in Science at UCB; a UCB physics department IBM postdoctoral fellow in condensed matter physics; a distinguished visiting research professor of the Beckman Institute at the University of Illinois, Urbana-Champaign; and a Bernard Osher Fellow at the San Francisco Exploratorium.