Michael Brennan may refer to:
- Michael Brennan (Lieutenant-General) Irish Defence Forces Chief of Staff 1931-1940
- Michael Brennan (actor) (1912–1982), film and television actor
- Michael Brennan (footballer) (born 1965), former Australian rules footballer
- Michael Brennan (field hockey) (born 1975), Australian field hockey player
- Michael Brennan (finance), finance professor
- Michael Brennan (Fine Gael) (died 1970), Irish Cumann na nGaedhael and (later) Fine Gael TD
- Michael Brennan (ice hockey) (born 1986), American professional ice hockey player
- Michael Brennan (Progressive Democrats) (born 1946), Irish Progressive Democrat Senator
- Michael Brennan (poet) (born 1973), Australian poet
- Michael F. Brennan, Mayor of Portland and former United States Democratic Party State Senator in Maine
- Mick Brennan (born 1950), Irish hurler