Sir John Byron (ca. 1526 – 1600) was an Elizabethan English landowner, nobleman, politician, and knight. He was also known as Little Sir John with the Great Beard.
He was the son of Sir John Byron (died 1567) and lived at Clayton Hall, Manchester, and later Royton, both then in Lancashire and later still at Newstead Abbey in Nottinghamshire, which he inherited from his father.
He was High Sheriff of Lancashire in 1572 and High Sheriff of Nottinghamshire in 1596. He was knighted by Queen Elizabeth I of England in 1579.
He married Alice Strelley and had four sons and three daughters. His eldest son was Anthony who died before him in 1587 and thus he was succeeded by his son Sir John Byron (died 1623). One of his daughters was married to Sir Thomas Hutchinson of Owthorpe, Nottinghamshire. Their daughter Margaret Hutchinson is an ancestor of U.S. President Andrew Jackson.