Hugh Annesley, 5th Earl Annesley (26 January 1831 – 15 December 1908) was a British military officer and Member of Parliament for County Cavan from 1857 to 1874.
He was the second son of William Richard Annesley, 3rd Earl Annesley. He was educated at Eton College.
He became a professional soldier and served in the Kaffir Wars in South Africa, 1851-1853. He was wounded in this war, and in the Crimean War his jaw was shattered at the Battle of the Alma in 1854. He became Colonel of the Scots Fusilier Guards in 1860. In 1874 his brother William Richard Annesley, 4th Earl Annesley, died unmarried, and Hugh succeeded as 5th Earl Annesley. In 1877, he was elected as a Representative Peer, serving until his death.
He was a pioneering amateur photographer. Thirty-five albums of his photographs are in the Public Record Office of Northern Ireland. They include pictures taken during the wars in South Africa and the Crimea, and during a visit to Japan, as well as photographs of his home, Castlewellan, and the surrounding area.
He married, first, Mabel Wilhelmina Frances Markham on 4 July 1877. He was 46 and she was 19. They had a daughter, Lady Mabel Annesley (1881–1959), who became well known as a water colour painter and wood engraver, and a son, Francis (born 25 February 1884). Francis became 6th Earl Annesley, but was killed in November 1914 in the First World War. Countess Mabel Annesley died at Castlewellan on 17 April 1891 (within three weeks of the death of Hugh's mother, The Dowager Countess Annesley, wife of the Third Earl, on 29 March 1891).