William Pitt could refer to:

• William Pitt, 1st Earl of Chatham (1708–1778), Prime Minister of Great Britain 1766-1768; often known as William Pitt the Elder
• William Pitt the Younger (1759–1806), his son and Prime Minister of Great Britain (1783-1801) and (1804-1806)
• William Pitt, Comptroller of the Household to King James I of England.
• William Rivers Pitt (born 1971), left-wing American essayist
• Bill Pitt (born 1937), British politician and Liberal Member of Parliament for Croydon North West 1981–1983
• William Pitt (architect) (1855-1918), Australian 19th century architect
• William Pitt (Canada), inventor of the underwater cable ferry in the early 1900s

William Pitt