| O.R.Jones(ed) |
| O'Brien, Conor Cruise |
| O'Brien, Edna |
| O'Callaghan, Bill |
| O'Connor, Ailsa |
| O'Connor, Barry |
| O'Donnell, E.E, |
| O'Donnell, John J. |
| O'Donnell, Terence |
| O'Donoghue, Ben |
| O'Donohue, Annette (compiled and researched by) |
| O'Dougherty, Margaret M (Butcher, James, ed) |
| O'Gorman, James F. |
| O'Grady, Colm |
| O'Hare, Eugene |
| O'Harris, Pixie |
| O'Kane, Frances |
| O'Leary, Timothy |
| O'Meara, Tim |
| O'Shea, Stephen |
| Oates, Nan and Brian Clarke |
| Odell, Carol |
| Odgers, George |
| Odum, Howard T. and Elizabeth C. Odum |
