John Mordaunt, Viscount Mordaunt (c. 1681 – 5 April 1710) was an English soldier and politician. The eldest son of Charles Mordaunt, 3rd Earl of Peterborough, he was a political ally of his father's and managed the attempt to impeach Lord Somers in the House of Commons in 1701. In 1708, he married Lady Frances Powlett (d. 1715), daughter of Charles Paulet, 2nd Duke of Bolton. They had two sons: * Charles Mordaunt, 4th Earl of Peterborough (1708–1779) * Lt.-Col. John Mordaunt (c. 1709–1767) He died of smallpox on 5 April 1710, and was buried at Turvey on 13 April.