Sir John St. John (by 1495 – 19 December 1558), of Bletsoe, Bedfordshire, was an English politician. He was the son of Sir John St John of Bletsoe and his wife Sybil, daughter of Rhys ap Morgan. He succeeded his father in 1525 and was knighted the following year. He was picked High Sheriff of Bedfordshire and Buckinghamshire for 1529–30, 1534–35 and 1549–50. He was a Member (MP) of the Parliament of England for Bedfordshire in 1529?, 1539 and 1542.