Sir John Mordaunt, 5th Baronet (by 1649 – 6 September 1721) of Walton d'Eiville was an English Tory politician who sat in the English and British House of Commons from 1698 to 1715. Mordaunt was the second son of Sir Charles Mordaunt, 3rd Baronet and his wife Catherine Tollemache, daughter of Sir Lionel Tollemache, 2nd Baronet, of Helmingham, Suffolk. He succeeded his elder brother to the baronetcy on 24 April 1665 and inherited the Massingham Estate at Little Massingham, Norfolk. Mordaunt was one of Warwickshire's two deputy-lieutenants and following the Rye House Plot was involved in organising arms searches in Warwickshire's main towns in 1683.