James Jeffrey Binney, FRS, FInstP (born 1950 in Surrey) is a British astrophysicist. He is a Professor of Physics at the University of Oxford and former head of the Sub-Department of Theoretical Physics as well as a Professorial Fellow at Merton College. Binney is known principally for his work in theoretical galactic and extragalactic astrophysics, though he has made a number of contributions to areas outside of astrophysics as well.