Charles Mordaunt, 3rd Earl of Peterborough and 1st Earl of Monmouth, was an English Army officer, Whig politician and peer. He was the son of John Mordaunt, 1st Viscount Mordaunt, and his wife Elizabeth, the daughter and sole heiress of Thomas Carey, the second son of Robert Carey, 1st Earl of Monmouth. Mordaunt's father, John Mordaunt, was created Viscount Mordaunt of Avalon and Baron Mordaunt of Reigate, Surrey, in 1659.

John Mordaunt, 1st Viscount Mordaunt was an English military officer and peer.