Isaac Maddox (27 July 1697 – 27 September 1759) was an Anglican clergyman, successively bishop of St Asaph and of Worcester. He was a member of the Royal Society. (No evidence has emerged to confirm a suggestion that he was the great nephew of wealthy land-owner Sir Benjamin Maddox (1644–1716).)
Isaac was the son of a Dissenter, Edward Maddox, stationer of London. He was orphaned at an early age, and brought up by an aunt who sent him to a charity school before apprenticing him to a pastry cook. However, assisted by an uncle, he quit his apprenticeship and was tutored by Rev. Hay, vicar of St Stephen Coleman Street. As a practising Dissenter, Maddox was given a grant from the Presbyterian Fund to study for the Dissenting ministry at Edinburgh University. Here he befriended John Horsley who later became the father of Samuel Horsley, who at that time was also destined for the Dissenting ministry. He was awarded M.A. in January 1722/3.
Maddox returned to London early in 1723 and, along with John Horsley, promptly conformed to the Church of England, though he remained on friendly terms with Dissenters, notably Philip Doddridge of Northampton; and he conspicuously supported foreign Moravian Christians in the North American colonies. In 1740, foreign Protestants after a residence of seven years could become naturalized on swearing an oath of allegiance. Quakers were exempted this oath. In 1747, with Maddox’s support, the exemption was extended to Moravians. In his speech in the House of Lords, Maddox insisted that