William Riddell (1807–1847) was a Roman Catholic bishop who briefly served as the Vicar Apostolic of the Northern District of England in 1847.^[1]

He was born at Felton Park, near Morpeth, Northumberland, England on 5 February 1807, the son of Ralph Riddell and Elizabeth Blount.^[1][2] He began his education at Stonyhurst College in Lancashire on 21 September 1817, and then to the English College, Rome on 29 November 1823, where he completed his theological studies.^[2] He was ordained a sub-deacon on 22 March 1828, a deacon in August 1829, and a priest in March 1830.^[1][2] After leaving Rome for England on 1 August 1830, he had a brief period as secretary to Cardinal Weld.^[2] In June 1832, he began as an assistant in the mission in Newcastle upon Tyne, and subsequently taking charge of the mission.^[3]

He was appointed coadjutor to the Vicar Apostolic of the Northern District, Bishop Francis George Mostyn, on 22 December 1843.^[1] On the same day, he was appointed Titular Bishop of Lagania, and was consecrated to the Episcopate by Bishop John Briggs on 17 March 1844.^[1] On the death of Bishop Mostyn on 11 August 1847, Riddell briefly succeeded as Vicar Apostolic of the Northern District.^[1]

He died in office at Charlotte Street, Newcastle upon Tyne on 2 November 1847, aged 40,^[1] of typhus contracted while ministering to the victims of an epidemic, and is buried in the vaults of St Mary's Cathedral, Newcastle upon Tyne.^[4]