William Pitt could refer to:

• William Pitt, 1st Earl of Chatham; Prime Minister of Great Britain 1766-1768; often known as William Pitt the Elder
• William Pitt the Younger; his son; 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, left-wing American essayist
• William Pitt, Liberal victor of the Croydon North West by-election, 1981 , normally known as Bill Pitt
• William Pitt, Australian 19th Century architect