Michael O'Brien
Michael or Mike O'Brien may refer to:
Politicians
- Michael O'Brien (Fianna Fáil politician), Irish councillor and mayor of Clonmel
- Michael O'Brien (Ohio politician), American politician in the state of Ohio
- Michael O'Brien (South Australian politician), Australian Labor Party member of the South Australian House of Assembly, 2002–present
- Micheal O'Brien (Canadian politician), Progressive Conservative Party of Canada candidate for the Canadian House of Commons
- Michael O'Brien (Victorian politician), Liberal Party of Australia member of the Victorian Legislative Assembly, 2006–present
- Michael H. O'Brien, American politician in the commonwealth of Pennsylvania
- Michael J. O'Brien, American politician in the state of Iowa
- Michael John O'Brien, Canadian politician, railway builder, industrialist and philanthropist
- Mike O'Brien (British politician), United Kingdom Labour Party politician
- Mike O'Brien (Canadian politician), mayor of Fredericton, New Brunswick
- Mike O'Brien (Seattle politician), American politician
- Michael O'Brien (New Hampshire politician)
Sports
- Michael O'Brien (Australian rules footballer), West Coast Eagles
- Michael O'Brien (fencer), Irish fencer
- Michael O'Brien (hurling manager), Irish Catholic priest and hurling manager
- Michael O'Brien (Irish sportsman), Irish association footballer, Gaelic footballer and cricketer in the 1920s
- Mike O'Brien (swimmer), American swimmer
- Micheál O'Brien, Irish Gaelic footballer and hurler
- Mike O'Brien (American football), American football player
- Mike O'Brien (hurler), Irish hurler
- Mikey O'Brien, Irish hurler
Others
- Michael O'Brien (bishop), Irish Roman Catholic bishop
- Michael O'Brien (American poet), American poet
- Michael O'Brien (Canadian author), Canadian author
- Michael O'Brien (game designer), Australian game designer
- Michael O'Brien (historian), American historian
- Michael O'Brien (unionist), American labor union leader
- Michael O'Brien (musician), American musician
- Michael O'Brien (photographer), American photographer
- Michael K. O'Brien, visual effects artist
- Mike O'Brien (actor), American writer and performer on Saturday Night Live
- Mike O'Brien (game developer), co-founder, ArenaNet; game designer and programmer
Characters
- Guardsman (Michael O'Brien), a fictional character in the Iron Man comics
- Michael O'Brien, a fictional engineer character in the 1940 Christmas film ''Beyond Tomorrow''