Joseph Brennan may refer to:
- Joseph Charles Brennan (1836–1872), English recipient of the Victoria Cross
- Joseph Brennan (civil servant) (1887–1963), Irish civil servant
- Joseph Brennan (Clann na Poblachta) (1889–1968), Irish Clann na Poblachta politician, 1948–1951
- Joseph Brennan (basketball) (1900–1989), American basketball player
- Joseph Brennan (Irish politician) (1912–1980), Irish Fianna Fáil politician and government minister
- Joseph Payne Brennan (1918–1990), American writer and poet
- Joseph E. Brennan (born 1934), U.S. politician, former Governor of Maine
- Joseph F. Brennan (born 1964), Pennsylvania politician