Sir John Mordaunt (died 1506) was an English landowner, barrister, and parliamentarian of the Tudor period, Speaker of the House of Commons.
The offices he held included Chancellor of the Duchy of Lancaster.
He was also summoned by Richard III to serve against the Scots in 1484, and fought for Henry VII at Stoke in 1487.
He was appointed High Steward of Cambridge University in 1504 and later the same year nominated to follow Sir Reginald Bray as Chancellor of the Duchy of Lancaster.
He had married Edith, coheir of Sir Nicholas Latymer, with whom he had at least two sons and a daughter.