For the M.P. murdered in 1840, see Lord William Russell.

William Russell, Baron Russell (29 September 1639 – 21 July 1683), was an English politician. He was a leading member of the Country Party, forerunners of the Whigs, who laid the groundwork opposition in the House of Commons of England to the concept of a reign of an openly Catholic King (James II) during the reign of King Charles II but ultimately resulted in his execution for treason, almost two years before King Charles died and James acceded to the throne.