William Riddell (1807–1847) was a Roman Catholic bishop.
William Riddell may also refer to:
James Riddell (skier) (born William James Riddell; 1909–2000), British skier and author W. G. Riddell (1865–1957), New Zealand magistrate W. J. B. Riddell (1899–1976), Scottish ophthalmologist William Renwick Riddell (1852–1945), Canadian lawyer, judge, and historian
See also William Riedell (1904–1952), American naval officer, engineer, and sports shooter William Biddell (1825–1900), British politician