William O'Reilly
William O'Reilly  or Bill O'Reilly may refer to:

 Bill O'Reilly (cricketer) (1905–1992), Australian cricketer
 Bill O'Reilly (political commentator) (born 1949), American commentator, author and television host
 William O'Reilly (MP) (1792–1844), UK MP for the Irish constituency of Dundalk, 1832–1835
 William O'Reilly (educator) (1864–1937), Irish educator
 William Edmund O'Reilly (1873–1934), British diplomat
 William F. B. O'Reilly (born 1963), American political consultant

See also
William Riley (disambiguation)