John St John, 11th Baron St John of Bletso

John St John, 11th Baron St John of Bletso (died 24 June 1757) was a British peer.

St John was the son of Andrew St John and his wife Jane Blois, daughter of William Blois of Cockfield Hall, Suffolk. He was the uncle of Paulet St John, 8th Baron St John of Bletso and succeeded his brother Rowland St John, 10th Baron St John of Bletso to the title of Baron St John of Bletso in 1722.

St John married Elizabeth Crowley (the daughter of Ambrose Crowley) of Greenwich on 6 March 1725. Their children included:

British comedian and actor Alexander Armstrong is a direct descendant of St John.