William Molyneux, 7th Viscount Molyneux (1685 – 30 March 1759) was a Jesuit priest and member of the peerage of Ireland. He was the third of four sons of . Following the death of their father in 1717 the title was initially held by the eldest brother, Richard, until he died without a male heir in 1738. It then passed to the second son, , who also died in 1745 leaving the title to William. He died on 30 March 1759 and the title passed to Thomas' son, Charles.