William Sandys, 1st Baron Sandys of the Vyne KG (1470 – 4 December 1540) was an English Tudor diplomat, Lord Chamberlain and favourite of King Henry VIII.
William was the son of Sir William Sandys of The Vyne, a Tudor mansion in Sherborne St. John, near Basingstoke, Hampshire, which the son greatly improved. It now belongs to the National Trust. His mother was his father's second wife, Margaret, the daughter of Sir John Cheney of Shurland on the Isle of Sheppey. As a young man, he gained preferment at Court and was soon associated with Prince Henry, assisting at his knighthood and the reception of Catherine of Aragon.
William remained a great friend of Henry when he became king and held a number of minor posts before becoming Treasurer of Calais in 1517. He was made a Knight of the Garter the following year (1518) and was apparently instrumental in organising the Royal meeting at the Field of the Cloth of Gold. He was made Baron Sandys of the Vyne soon afterwards. He became Lord Chamberlain in 1526 and Henry visited him three times at the Vyne, once with Anne Boleyn whom Sandys was later to escort to her imprisonment in the Tower. Although his sister Edith had married Lord Darcy, one of the leaders of the Pilgrimage of Grace, there is no evidence that Sandys played any part in the uprising, or that he sympathised with it.