John Ellis (October 4, 1874 – September 20, 1932) was a British executioner from 1901 to 1924.

John Ellis is a British theoretical physicist born in 1946. He attended Cambridge University, and led the particle theory group at CERN for six years. He is best known for assisting Dimitri Nanopoulos in the unification of string theory with the Standard Model.

John Ellis (1789-1862) of Beaumont Leys in Leicestershire was instrumental in interesting George Stephenson in the proposed Leicester and Swannington Railway.