John Graham Shepherd (born 1946) CBE FRS is a British Earth system scientist, Emeritus Professor at University of Southampton, and a former director of the National Oceanography Centre, Southampton. He has worked on a wide range of environment-related topics, including the transport of chemical tracers in the atmospheric boundary layer and in the deep ocean, the management of marine fish stocks, and the dynamics of the Earth system. More recently he led a comprehensive review of geoengineering for the Royal Society.