Sir William Middleton, 3rd Baronet of Belsay Castle, Bolam, Northumberland, was a British landowner and Whig politician who sat in the House of Commons for 35 years from 1722 to 1757.
- Occupation
- politician
- Position held
- member of the 8th Parliament of Great Britain, member of the 7th Parliament of Great Britain, member of the 6th Parliament of Great Britain, member of the 9th Parliament of Great Britain
- Citizenship
- Kingdom of Great Britain
- Born
- 1705
- Died
- September 28, 1757
