John de Beauchamp, 1st Baron Beauchamp de Warwick KG (c. 1316 – 2 December 1360) was the third son of Guy de Beauchamp, 10th Earl of Warwick, and brother of Thomas de Beauchamp, 11th Earl of Warwick, with whom he became a founder and the tenth Knight of the Order of the Garter in 1348.
He attended King Edward III into Flanders in 1338, was in the array at Vironfosse in 1339, and shared the glory of the great naval victory off Sluys in 1340. He carried the Royal Standard at the Battle of Crécy in 1346 and was present at the siege and surrender of Calais, of which town he was appointed captain in 1348. He also held the posts of Admiral of the Fleet, Constable of the Tower of London and Warden of the Cinque Ports. He was summoned to Parliament as a Baron in 1350.
He died without issue and his barony expired. His remains were interred, between two pillars, before the image of the Virgin, on the south side of the nave of Old St Paul's Cathedral, where there was a monument to his memory, incorrectly later known as Duke Humphrey's Tomb, because of the mistaken belief that it was the tomb of Humphrey of Lancaster, 1st Duke of Gloucester. The grave and monument were destroyed along with the old cathedral in the Great Fire of London in 1666. A modern monument in the crypt lists Beauchamp as one of the important graves lost.