John Mordaunt, 1st Baron Mordaunt (died 18 August 1562) was an English politician and peer.
He was the son of John Mordaunt of Turvey, Bedfordshire, who was MP and speaker of the house. He was admitted to the Middle Temple in 1503 to be trained as a lawyer.
He was made a Knight of the Bath when the future Henry VIII was created Prince of Wales on 18 February 1503. He succeeded his father in 1504, inheriting his Bedfordshire estates, and was appointed High Sheriff of Bedfordshire and Buckinghamshire for 1509. He was a member of Henry VIII's court and was with him at the Field of the Cloth of Gold in 1520 and a member of his council in 1526 and was created Baron Mordaunt in 1529. He took his seat in the House of Lords in 1532.
He became active in local government and rarely visited Parliament, especially after an accident in 1539.
He died in 1562 and was buried in Turvey church alongside his wife, who had predeceased him. He had married Elizabeth Vere, daughter and coheir of Sir Henry Vere of Great Addington, Northamptonshire. They had four sons and four daughters. He was succeeded by his eldest son John Mordaunt, 2nd Baron Mordaunt. His second son Edmund became MP for Bedford.