Sir John Meldrum (died 1645) was a soldier of Scottish origin who spent 36 years in the service of the Stuart kings of Scotland and England, James VI and I and Charles I. In 1636, Meldrum was granted by letters-patent from the king licence to continue and renew the lighthouses erected by Charles I on the North and South Forelands. In 1642, he found himself opposed to the policies of Charles' government and supported the Parliamentarian cause in the Civil War. His most notable action was his defeat by Prince Rupert at the relief of Newark in early 1644. He also directed the successful construction of a firing platform in Gosport during the Siege of Portsmouth. He was killed during the Great Siege of Scarborough Castle.