William Keatinge Clay (1797–1867) was an English cleric and antiquary.
Clay was born in 1797, and, having been ordained deacon in 1823 by John Fisher, Bishop of Salisbury, became curate of Greenwich. He was ordained priest in the following year by William Howley, Bishop of London. He was curate of Paddington in 1830, and of Blunham, Bedfordshire, in 1834. In 1835 he took the degree of B.D. at Jesus College, Cambridge, as a 'ten-year man';