Slingsby Bethell (1695–1758) of Tower Hill, London was an English Member of Parliament. ^[1]

He was the 3rd son of William Bethell of Swindon and the younger brother of Hugh Bethell. In his early life he bought a plantation in Antigua and returned to work in London as a well-to-do merchant involved in the Africa trade.

He was a member of the Fishmongers’ Company from 1749 to his death, an alderman of London in 1749, Sheriff of the City of London for 1751-52, and Lord Mayor of London for 1755-56. He was Member of Parliament for the City of London from 1747 to November 1758.

He died unmarried in 1758.