Lawrence O'Brien or Larry O'Brien could refer to:
- Larry O'Brien (1917–1990), American politician and basketball commissioner
- Larry O'Brien Championship Trophy, award presented by the National Basketball Association to the winner of the NBA Finals, named for the above
- Larry O'Brien (Canadian politician) (born 1949), former mayor of Ottawa, Ontario
- Lawrence D. O'Brien (1951–2004), member of the Canadian House of Commons from Labrador
- Larry O'Brien, former director of the Glenn Miller Orchestra