Authors
- John O'Connor
- Kaori O'Connor
- Margaret A. O'Connor
- Martin O'Connor
- Mary Ellen O'Connor
- Michael O'Connor
- Mike O'Connor 4
- Mrs. Armel O'Connor
- Neal W. O'Connor
- P. Fitzgerald O'Connor
- P.A. O'Connor
- Patrick J. O'Connor 3
- Paul O'Connor
- Peter O'Connor
- Philip O'Connor
- Raymond J. O'Connor 1
- Richard O'Connor
- S.J. O'Connor
- Sally O'Connor
- Scott O'Connor
- T.F. O'Connor
- T.P. O'Connor
- Terry O'Connor 1
- Thom O'Connor
- Tom O'Connor
- Ulick O'Connor
- W.H. O'Connor
- Joseph O'Conor
- Sean O'Crohan
- Tomas O'Crohan
- Enid O'Dare
- O'Daulas
- Deirdre O'Day
- Rosemary O'Day
- James O'Dea
- Keller O'Dea
- Solman O'Dea
- Thomas F. O'Dea
- A.C. O'Dell
- Andrew C. O'Dell
- George O'Dell
- Noreen O'Dell
- Robin O'Dell
- Roy O'Dell 2
- Scott O'Dell
- John O'Dhea
- O'Doherty
- Brian O'Doherty
- C. O'Doherty
- T.A. O'Donahue
- Peter O'Donald
- E.E. O'Donnell
- Elliot O'Donnell
- Elliott O'Donnell
- G.M. O'Donnell
- James P. O'Donnell
- Kevin O'Donnell
- Mabel O'Donnell
- Michael O'Donnell
- Mike O'Donnell
- P.A.T. O'Donnell
- Peter O'Donnell
- Sean O'Donnell
- Bernard O'Donoghue
- Brendan O'Donoghue 1
- D.J. O'Donoghue
- John O'Donoghue
- Kevin O'Donoghue 2
- M. O'Donoghue
- Yolande O'Donoghue
- Maureen O'Donoughue
- William O'Donoughue
- Katherine O'Donovan
- Cathy O'Dowd
- George O'Dowd
- Mary O'Dowd
- Mary Ann O'Dowd
- Brendan O'Dowda
- O'Driscoll
- Catherine O'Driscoll
- Robert O'Driscoll
- Martin O'Dwyer
- S. O'Dwyer
- Sir Michael O'Dwyer
- P O'Erbe
- Eileen O'Faolain 1
- Nuala O'Faolain
- Sean O'Faolain
- John O'Farrell
- Kathleen O'Farrell
- Padraic O'Farrell
- Patrick O'Farrell
- R.C. O'Farrell
- Valerie O'Farrell
- Liam O'Flaherty
- Louis O'Flaherty
- O'Gorman
- Connie O'Gorman
- Edmundo O'Gorman
- Francis O'Gorman