Walter Francis John Montagu Douglas Scott, 9th Duke of Buccleuch and 11th Duke of Queensberry, KT, VRD, JP, DL (28 September 1923 – 4 September 2007) was a Scottish Peer, politician, and landowner. He served in the Royal Naval Volunteer Reserve in the Second World War, and represented Edinburgh North in the House of Commons for 13 years.
He owned the largest private landed estate in the United Kingdom, covering some 280,000 acres (1,100 km2). The estate includes Drumlanrig Castle in Dumfries and Galloway, Bowhill House in Selkirkshire, and Boughton House in Northamptonshire. A fourth house, Dalkeith Palace, near Edinburgh, is let to the West Central Wisconsin Consortium, which uses the palace as a base for its study abroad program.
Walter Francis John Montagu Douglas Scott was best known by his middle name John, and he was the only son of Walter Montagu Douglas Scott, 8th Duke of Buccleuch & 10th Duke of Queensberry, and the former Mary Lascelles. His paternal aunt was Princess Alice, Duchess of Gloucester. His sister Elizabeth married the 10th Duke of Northumberland, and Caroline wed politician Ian Gilmour.