General John Mostyn (c.1709 – 16 February 1779) was a British soldier, MP and colonial administrator.
He was a younger son of Sir Roger Mostyn, 3rd Baronet and educated at Westminster School and Christ Church, Oxford.
On 2 April 1745, he was promoted to captain of a company, and was wounded the next month at the Battle of Fontenoy.
[1] He served as Groom of the Bedchamber to King George II from 1746 to his death.
It was an appointment in name only, and Mostyn was not in residence on the island, which meant that his deputy was in effective charge – from 1774 this was James Murray, his eventual successor who was forced to surrender the island in 1782 to a Spanish force.