Charles William Slingsby "Sim" Duncombe, 3rd Earl of Feversham DSO (2 November 1906 – 4 September 1963), styled the Hon. Charles Duncombe until 1915 and then Viscount Helmsley until he succeeded his father in 1916, was a British Conservative politician.
Feversham was the eldest son of Charles Duncombe, 2nd Earl of Feversham, and his wife Lady Marjorie Blanche Eva, daughter of Francis Greville, 5th Earl of Warwick, and was educated at Eton. He succeeded in the earldom in 1916, aged only nine, when his father was killed in the First World War.
Feversham took his seat on the Conservative benches in the House of Lords and served under Ramsay Macdonald and Stanley Baldwin as a Lord-in-Waiting (government whip in the House of Lords) from 1934 to 1936 and under Baldwin and later Neville Chamberlain as Parliamentary Secretary to the Ministry of Agriculture and Fisheries and Deputy Minister of Fisheries from 1936 to 1939.
Feversham was also a Lieutenant-Colonel in the 13th/18th Royal Hussars and an Honorary Colonel in the Queen's Own Yorkshire Yeomanry and fought in the Second World War, where he was awarded the Distinguished Service Order in 1945.
Feversham was Treasurer of the University of Leeds from 1959 to his death.