William Dool Killen (1806–1902) was an Irish Presbyterian minister and church historian.Born at Church Street, Ballymena, County Antrim, on 16 April 1806, he was third of four sons and nine children of John Killen (1768–1828), a grocer and seedsman in Ballymena, by his wife Martha, daughter of Jesse Dool, a farmer in Duneane. His paternal grandfather, a farmer at Cammoney, married Blanche Brice, a descendant of Edward Brice; a brother, James Miller Killen (1815–1879) was minister in Comber, County Down. Thomas Young Killen was his father's great-nephew.[1]