John Brennan
John Brennan may refer to:
Public officials
- Jack Brennan, U.S. Marine officer and aide of Richard Nixon
- John O. Brennan, former CIA director
- John P. Brennan, Democratic politician in the U.S. state of Ohio
- John Brennan Hussey, former mayor of Shreveport, Louisiana
- John Joseph Brennan, Northern Ireland politician
- John Brennan (Irish senator), Fianna Fáil politician
- John A. Brennan Jr., American lobbyist and Massachusetts politician
Sports
- J. J. Brennan, Irish hurler
- John Brennan (Derry Gaelic footballer), Gaelic football manager and player
- John Brennan (Kerry Gaelic footballer), former Gaelic footballer
- Jack Brennan (footballer, born 1892), English footballer for Bradford City and Manchester City
- John Brennan (American football), American football player
- Jack Brennan (baseball), American baseball catcher
- John Brennan (athlete), American track and field athlete
Artists
- Johnny Brennan, American actor, screenwriter and voice actor
- John Wolf Brennan, Irish pianist, organist and composer
Other people
- John J. Brennan (businessman), chairman and CEO of The Vanguard Group
- John Calder Brennan, U.S. historian
- John Brennan (doctor), Irish doctor
- Sidney Czira, Irish journalist and revolutionary known by her pen name "John Brennan"
- John N. H. Brennan, Irish author, huntsman and solicitor
- John P. Brennan (priest), first American Catholic priest to declare bankruptcy
- John W. Brennan, United States Army general