William O'Brien (disambiguation)
William O'Brien was an Irish journalist and politician.
William O'Brien may also refer to:
Other politicians
- William O'Brien, 2nd Earl of Inchiquin, Governor of Jamaica
- William O'Brien , New South Wales politician
- William O'Brien , Irish Fine Gael TD and Senator from County Limerick
- William O'Brien , American politician
- William O'Brien , political figure in Nova Scotia
- William O'Brien , American state legislator in Rhode Island
- William O'Brien , Irish Labour TD and trade union leader
- William Edward O'Brien, lawyer, farmer, editor and political figure in Ontario, Canada
- William H. O'Brien, Wisconsin state assemblyman
- William J. O'Brien , United States Representative from Maryland, 1873–1877
- William L. O'Brien, former Speaker of the New Hampshire House of Representatives
- William Smith O'Brien, Irish Conservative and Repeal MP and Young Ireland revolutionary
- William Smith O'Brien , U.S. Representative from West Virginia
- Bill O'Brien , British Labour MP for Normanton, 1983–2005
- Billy O'Brien , American politician in the Virginia House of Delegates
In sports
- William O'Brien , head football coach for the Southern Illinois Salukis
- William O'Brien , Scottish footballer
- William O'Brien , American racing driver
- Parry O'Brien, American shot-put innovator
- William O'Brien, National League baseball umpire in 1876
- Willie O'Brien, English footballer
- Bill O'Brien , American football halfback
- Bill O'Brien , American football coach
- Bill O'Brien , Australian rules footballer for Collingwood
- Bill O'Brien , Australian rules footballer for St Kilda
- Bill O'Brien , Australian rules footballer for South Melbourne
- Billy O'Brien , Major League Baseball first baseman
- Billy O'Brien , Welsh football goalkeeper
Others
- William O'Brien, 2nd Marquess of Thomond, Irish peer
- William O'Brien, 3rd Earl of Inchiquin, Irish peer
- William O'Brien, 4th Earl of Inchiquin, founder of the Royal Cork Yacht Club in 1720
- William O'Brien , Irish actor in the company of David Garrick at Drury Lane
- William O'Brien , Irish judge
- William O'Brien , American police officer
- William O'Brien , British admiral
- William O'Brien, President, BATS Global Markets
- William B. O'Brien, founder and the president of the World Federation of Therapeutic Communities also co-founder of Daytop
- William David O'Brien, auxiliary bishop of Chicago, Illinois, USA
- William J. O'Brien , United States Army officer during World War II
- William J. O'Brien, inventor of the Decca Navigator System
- William P. O'Brien , American police officer
- William S. O'Brien, American businessman
- Bill O'Brien , Director of Theatre and Musical Theatre for the National Endowment for the Arts; actor
- Tim O'Brien , American author
- Billy Porter , American burglar and underworld figure in New York City
- William O'Brien , Irish professor of archaeology in University College Cork.
- Billy O'Brien, film director whose work includes I Am Not a Serial Killer
- Billy O'Brien, child actor who appeared in films including ''The Lone Trail''
Things
- SS William O'Brien, steam cargo ship built in 1914–1915 by New York Shipbuilding Company of Camden, foundered in April 1920