John Brennan may refer to:
- People
- John Brennan (American football) (1913-1982), American football player
- John Brennan (athlete) (1879–1964)
- John Brennan (Gaelic footballer) (born 1937), Derry football manager
- John Brennan (Irish senator) (1901–1977)
- John Brennan (Vanguard CEO) (born 1954), Chairman and CEO of The Vanguard Group
- John Calder Brennan (1908–1996), historian
- John G. Brennan (born 1961), American actor, screenwriter and voice actor
- John Joseph Brennan (1913–1976), Northern Ireland politician
- John O. Brennan (born 1955), Deputy National Security Advisor to U.S. President Obama; CIA Director nominee
- Jack Brennan (born 1937), U.S. Marine officer and aide of Richard Nixon
- May also refer to
- John Brennan Hussey (born 1934), former mayor of Shreveport, Louisiana
- Fictional characters
- John Brennan, a character in the play Coyote on a Fence
Famous quotes containing the word john:
“Of all the men who were said to be my contemporaries, it seemed to me that John Brown was the only one who had not died.”
—Henry David Thoreau (1817–1862)