William Richard Annesley, 4th Earl Annesley (21 February 1830 – 10 August 1874), styled Viscount Glerawley until 1838, was an Irish-born British Conservative politician.

Born at Rutland Square (now Parnell Square), Dublin, Annesley was the eldest son of William Annesley, 3rd Earl Annesley, by his second wife Priscilla Cecilia, daughter of Hugh Moore.^[1] He was educated at the University of Cambridge.^[1]

Annesley succeeded in the earldom in August 1838 on the death of his father.^[1] As this was a title in the Peerage of Ireland it did not entitle him to a seat in the House of Lords. He was instead elected to the House of Commons for Great Grimsby in the 1852 general election, a seat he held until 1857. In 1867 he was elected an Irish representative peer, which he remained until his death.

He inherited the Castlewellan Estate in County Down and built Castlewellan Castle on the estate c.1856.

Lord Annesley died at Cowes, Isle of Wight, in August 1874, aged 44. He was unmarried and was succeeded in his titles by his younger brother, Hugh.