Jack Brennan (disambiguation)

Jack Brennan (1937–2023) was a United States Marine Corps officer and political aide.

Jack Brennan may also refer to:


 * Jack Brennan (baseball) (1862–1914), American baseball catcher
 * Jack Brennan (footballer, born 1892) (1892–1942), English footballer
 * Jack Brennan (Australian footballer) (1897–1987), Australian rules footballer
 * Jack Brennan (rugby league), English rugby league footballer