Sir Roger James Elliott FRS (born 8 December 1928 in Chesterfield) is a British theoretical physicist specialising in the magnetic, semiconductor and optical properties of condensed matter.
Elliott obtained a DPhil in mathematics and theoretical physics from the University of Oxford in 1952. He was a research fellow at the University of California, Berkeley in 1952–3, then at the Atomic Energy Research Establishment until 1955, when he was appointed to a lecturership at the University of Reading. He returned to the University of Oxford in 1957, where he was the Wykeham Professor of Physics from 1974 until 1988. He served as chief executive of Oxford University Press from 1988 until 1993.
The Institute of Physics awarded the Maxwell Medal and Prize jointly to Elliott and Kenneth Stevens in 1968, and the Guthrie Medal and Prize to Elliott in 1990. Elliott was elected a fellow of the Royal Society in 1976 and knighted in 1987. He has been awarded honorary Doctor of Science degrees by the universities of Paris (1983), Bath (1991) and Essex (1993).
He is the cousin of mathematician Robert J. Elliott.