William Downes Willis (9 September 1790 – 22 October 1871) was a British clergyman, theologian, and author on religious subjects. Willis was the son of William Willis and Mary, daughter of landowner Robert Hamilton Smyth, of Lismore, Co. Down, of the family of the Viscounts Strangford. He was born at Dublin, where his father, an Army Captain, was then stationed. His middle name came from his paternal grandmother; the Downes family, of Rotherham, were wool merchants and yeoman landowners who married into the landed gentry Kent family of Kimberworth.