Pat O'Brien

Politicians

• Pat O'Brien (Irish politician), Irish Nationalist MP in the United Kingdom Parliament
• Pat O'Brien (Canadian politician), member of the Canadian House of Commons
• Patrick Joseph O'Brien, , Irish Nationalist MP in the United Kingdom Parliament

  Others

• Benson Harrison "Pat" O'Brien of Pat O'Brien's Bar, US cocktail maker
• Pat O'Brien (actor), American film actor
• Maynard O'Brien, American sports commentator and television host
• Pat O'Brien (guitarist), American guitarist for Cannibal Corpse
• Pat O'Brien (racing driver), Hall of Fame modified racing driver
• Pat O'Brien (rugby union), South African rugby union player