William Wickham (11 November 1761 – 22 October 1840) was a British spymaster and a director of internal security services during the French Revolutionary Wars. He was credited with disrupting radical conspiracies in England but, appointed Chief Secretary for Ireland, failed in 1803 to anticipate a republican insurrection in Dublin. He ended his career in government service in 1804, resigning his post in Ireland where, privately, he denounced government policy as "unjust" and "oppressive".