William O'Neill
William, Billy or Bill O'Neill may refer to:
Politics
- Bill O'Neill , former member of the Ohio House of Representatives
- Bill O'Neill , member of the New Mexico Senate
- C. William O'Neill, Governor of Ohio
- William O'Neill , appellate judge and 2008 candidate for U.S. Representative from Ohio's 14th congressional district
- William A. O'Neill, Governor of Connecticut, 1980–1991
- William P. O'Neill, Lieutenant Governor of Indiana
Sports
- Bill O'Neill , American football player
- Bill O'Neill , American baseball player
- Bill O'Neill , American professional ten-pin bowler
- Bill O'Neill , New Zealand lawn bowler
- Billy O'Neill , Welsh rugby player
- William O'Neill , Irish rugby union player
- Billy O'Neill , Irish former Gaelic football and hurler
- Billy O'Neill , Irish footballer
- Willie O'Neill , Scottish footballer
- Willie O'Neill , Irish hurler
- Willie O'Neill , Irish hurler and Gaelic footballer
- Willie O'Neill , Irish international footballer
Others
- Bill O'Neill , News Corporation executive
- Buckey O'Neill, Old West sheriff and U.S. Army officer killed at the Battle of San Juan Hill
- William F. O'Neil, founder of General Tire and Rubber Company
- William O'Neill, 1st Baron O'Neill, Anglo-Irish hereditary peer, clergyman and musical composer
- William O'Neill , American soldier in the Indian Wars