Charles William Wentworth Fitzwilliam, 5th Earl Fitzwilliam in the peerage of Ireland, and 3rd Earl Fitzwilliam in the peerage of Great Britain, KG (4 May 1786 – 4 October 1857) was a British nobleman and politician. He was President three times of the Royal Statistical Society in 1838–1840, 1847–1849, and 1853–1855; and President of the British Association for the Advancement of Science in its inaugural year (1831–2). He was born the only son of William Fitzwilliam, 4th Earl Fitzwilliam and his first wife, Lady Charlotte Ponsonby. He was a pupil at Eton College from 1796 to 1802.