John Spencer-Churchill, 11th Duke of Marlborough

John George Vanderbilt Henry Spencer-Churchill, 11th Duke of Marlborough, styled Earl of Sunderland until 1934 and Marquess of Blandford between 1934 and 1972, was a British Army officer and peer. He was the elder son of the 10th Duke of Marlborough and his wife, the Hon. Mary Cadogan. He was known as "Sunny" after his childhood courtesy title of Earl of Sunderland.