William King (1663–1712) was an English poet.
Born in London, the son of Ezekiel King, he was related to the family of Edward Hyde, 1st Earl of Clarendon. From Westminster School, where he was a scholar under Richard Busby, at the age of eighteen he was elected to Christ Church, Oxford in 1681. There he is said to have dedicated himself completely to his studies. Reportedly after eight years he had read over 22,000 books and manuscripts, a figure reduced to about 7,000 in seven years by Thomas Young.
In 1688 he graduated M.A. Taking up the civil law, he became Doctor in 1692, and was admitted an advocate at Doctors' Commons. In 1702, having moved to Ireland, he was made Judge of the Admiralty, Commissioner of the Prizes, Keeper of the Records in Birmingham's Tower, and Vicar-General to Narcissus Marsh, the primate. King found a friend in Anthony Upton, one of the High Court judges, who had a house called Mountown, near Dublin, where King frequently stayed. Both men were severely criticised by their political opponents for neglecting their official duties: it was said that they had no thought but to live out their days in rural retirement.
In 1708, when Lord Wharton was sent to govern Ireland, King returned to London.
In 1710 he became a supporter of the High Church party, on the side of Henry Sacheverell; and was supposed to have had some part in setting up The Examiner. He was suspicious of the operations of Whiggism; and he criticised White Kennet's adulatory sermon at the funeral of the Duke of Devonshire.