- O'Connor, Nathaniel J1
- O'Keefe, Aidan J1
- O'Neil, Alexander Benjamin1
- O'Shea, Christopher1
- O'Shea, Colleen E1
- Obiora, Obianuli Ebubechukwu1
- Okada, Haruna1
- Opare-Sem, Yaw1
- Ortiz, Miguel Antonio1
- Osler, Mary Ellen B1
- Otis Mattiuzzi, Benjamin Milton1
- Otoo, Naomi1