John Simpson FInstP (born 23 March 1958) is a British nuclear physicist. He is known for his work in gamma-ray spectroscopy and detector design. He was Head of Technology, Division of Technology Department. and was Head of the Nuclear Physics Group at STFC Daresbury Laboratory. He is a Visiting Professor of Physics at the University of Liverpool. Simpson was educated at University of Liverpool (BSc(Hons) Physics Class 1, 1979) and the University of Liverpool (PhD, 1983).