| Surname | Country | Prov/State | Earliest | Latest | Contact Details |
|---|
| ODINGSELLS | ENG | WAR | 1100 | 1300 | Jean Ostrowski: 305-270 Simcoe Street, Victoria, BC V8V 1K7 |
| O'HARA | ENG | NBL | - | 1943 | Ann Young
|
| OKONOR | ENG | LIN | 1370 | 1395 | Jean Ostrowski: 305-270 Simcoe Street, Victoria, BC V8V 1K7 |
| OLDNALL | ENG | STS | 1848 | - | Ruth Peterson
|
| OLIVER | CAN | BC | - | 1944 | Gael Huntley
|
| O'MALIA | USA | NY, OH, IA | 1819 | Present | Helen O'Malia: 1211 Old Esquimalt Road, Victoria, BC V9A 4X7 |
| O'MALIA | IRL | MAY | 1819 | Present | Helen O'Malia: 1211 Old Esquimalt Road, Victoria, BC V9A 4X7 |
| O'NEILL | ENG | NBL | 1864 | - | Ann Young
|
| ORMANDY | ENG | LAN | 1720 | 1750 | Lorraine Toleikis
|
| ORMISTON | CAN | ON | 1850 | 1914 | Gerald & Dorothy Nelson
|
| ORMISTON | SCT | - | 1817 | 1850 | Gerald & Dorothy Nelson
|
| OSWALD | SCT | FIF | 1775 | 1816 | Anne Morecraft
|
| OVERTON | ENG | LIN | 1760 | - | Jean Ostrowski: 305-270 Simcoe Street, Victoria, BC V8V 1K7 |
