Sir John Say (died 12 April 1478) was an English courtier, MP and Speaker of the House of Commons.
He was the son of John Say, born before 1445, and his wife Maud. His brother, [Master] William Say, was Dean of the Chapel Royal, Master of the Hospital of St Anthony, London and Dean of St Paul’s. Sir John owned land at Baas, Broxbourne, Little Berkhamsted and Sawbridgeworth, Hertfordshire, and Lawford, Essex
Sir John Say trained as a lawyer and became a King's Serjeant, Coroner of the Marshalsea, Yeoman of the Chamber and Crown, Keeper of Westminster Palace, Squire of the Body and Privy Councillor.
In 1447 he entered Parliament as MP for Cambridge and was then in 1449 elected Knight of the Shire for Cambridgeshire, when he was also elected Speaker of the House of Commons. In June 1449 he was made Chancellor of the Duchy of Lancaster and in 1449 was appointed sheriff of Norfolk and Suffolk. By 1450, he was out of favor and in 1451 the Commons demanded his banishment from the court. However, he was pardoned in 1452.