William Reilly

William Reilly may refer to:
 * William K. Reilly (born 1940), Environmental Protection Agency administrator
 * William L. Reilly (1916–2009), American Jesuit and academic
 * William J. Reilly (1899–1970), American economist
 * William Edward Moyses Reilly (1827–1886), British Army general
 * William Arthur Reilly (1903–1969), American political figure from Boston
 * Bill Reilly (William Francis Reilly, 1938–2008), American publishing and media executive
 * Bill Reilly (athlete) (William L. Reilly, born 1943), American steeplechase runner
 * Will Reilly (born 2002), American soccer player
 * William K. Reilly, pseudonym used by English writer John Creasey (1908–1973)