- O'Brien, Catherine Hannah1
- O'Brien, Christopher Joseph1
- Obasare, Ricardo Ejovi1
- Oliva, Andrew Alexander1
- Oliveira, Thales Rodrigues1
- Oliver, Michael James1
- Oliveri, Michael Leo1
- Orsi, Edward Paul1
- Oshiro, Franco Antonio1
- Over, Robert A1
- Owen, Archibald Alexander1