Richard John Eden OBE (2 July 1922 – 25 September 2021) was a British theoretical physicist who researched quantum field theory, nuclear theory and S-matrix theory in the 1950s and 1960s.
In 1974 he founded the Energy Research Group at the Cavendish Laboratory in Cambridge and from 1982 to 1989 was Professor of Energy Studies there. From 1974, he served on the UK Advisory Committee for Energy Conservation.
He was a founding Fellow of Clare Hall, Cambridge in 1966, and from 1987 to 1999 he was vice president of the college. After retirement he was made an Honorary Fellow.