William Andrew Goddard III (born March 29, 1937 in El Centro, California, U.S.) is the Charles and Mary Ferkel Professor of Chemistry and Applied Physics, and Director, Materials and Process Simulation Center at the California Institute of Technology. He obtained his B.S. from the University of California, Los Angeles, in 1960 and his Ph.D. from the California Institute of Technology, 1965. After his Ph. D. he remained at the California Institute of Technology as Arthur Amos Noyes Research Fellow (1964–66), Professor of Theoretical Chemistry (1967–78) and Professor of Chemistry & Applied Physics (1978-).
Goddard has made many contributions to theoretical chemistry, such as the generalized valence bond (GVB) method for ab initio electronic structure calculations and the ReaxFF force field for classical molecular dynamics simulations.
He is a member of the International Academy of Quantum Molecular Science and the U.S. National Academy of Sciences.
In August 2007, the American Chemical Society at its biannual national convention celebrated Goddard's 70th birthday with a 5-day symposium titled, "Bold predictions in theoretical chemistry."