John Hussey Hamilton Vivian, 4th Baron Swansea (1 Jan 1925 – 24 June 2005) was a British peer, sports shooter and lobbyist notable for his role in the debate over gun control in the United Kingdom. He was educated at Eton College and Trinity College, Cambridge, where he graduated with a degree in French and German. He succeeded his father to the Barony in 1934 and took his seat in the House of Lords in 1956. He was Deputy Lieutenant for Powys in 1962. In 1966, Vivian, as Lord John Swansea, represented Wales in the Commonwealth Games, where he took Gold in the Full Bore Rifle event. He took a Silver in the same event at the 1982 Commonwealth Games in Brisbane.