John Monckton (1695 – 15 July 1751) was a British 18th century Whig politician. He was elevated to the Irish peerage as the first Viscount Galway.
John Monckton was the eldest son of Robert Monckton (1659–1722), lord of the manors of Cavil, near Howden, and Hodroyd, near Barnsley, Yorkshire. A strong opponent of the policies of James II, Robert Monckton had gone into exile in the Netherlands and returned with the invading army of William III in the Glorious Revolution of 1688. This established a strong family connection with the Whig party and Robert had gone on to win the borough of Pontefract from the Tories in the general election of 1695, and later to represent Aldborough. Robert's wife, and John's mother, was Theodosia Fountaine, an heiress from Melton, East Riding of Yorkshire. John Monckton was educated at Trinity Hall, Cambridge, which he entered in 1713.
Monckton stood unsuccessfully as a Whig candidate for Clitheroe at the election of 1722. Victory in the seat depended on control of burgages. Having bought a number of burgages to no effect, Monckton decided to sell them to Sir Nathaniel Curzon, one of the victorious Tory candidates. As part of the deal, Curzon deferred to Monckton for the following parliament, and he was duly elected MP for Clitheroe on 23 August 1727, holding the seat until 1734. On 17 July 1727 the grateful Whig government of Robert Walpole made Monckton Viscount Galway and Baron of Killard, both in the Irish peerage. An Irish peerage allowed the holder to continue sitting in the British parliament, and was a way of honouring a useful political ally.