Pat O'Brien may refer to:
Politicians
edit- Pat O'Brien (Canadian politician) (born 1948), member of the Canadian House of Commons
- Pat O'Brien (Irish politician) (c. 1847–1917), Irish Nationalist MP in the United Kingdom Parliament
Others
edit- Pat O'Brien (actor) (1899–1983), American film actor
- Pat O'Brien (guitarist) (born 1965), American guitarist for Cannibal Corpse
- Pat O'Brien (radio and television personality) (born 1948), American sports commentator and television host
- Pat O'Brien (rugby union) (born 1989), South African rugby union player
- Pat O'Brien of Pat O'Brien's Bar, US cocktail maker
- Maynard O'Brien, American football coach nicknamed Pat
- Pat O'Brien (racing driver), 4 time Mr. Dirt 358 Modified Champion