554 results
| Oliver | 928 |
| Office | 923 |
| Olivier | 755 |
| Osborne | 646 |
| Owen | 622 |
| O'brien | 605 |
| O'connor | 580 |
| Olsen | 543 |
| O'neill | 461 |
| Orr | 320 |
| O'sullivan | 300 |
| O'connell | 292 |
| Old | 289 |
| Otto | 283 |
| O'donnell | 269 |
| Owens | 223 |
| Opperman | 189 |
| Ocean | 188 |
| Omar | 182 |
| Oberholzer | 180 |
| O'leary | 174 |
| Ormsby | 156 |
| Orange | 152 |
| Ogle | 147 |
| Osman | 146 |
| O'reilly | 138 |
| Oakley | 118 |
| Oliphant | 114 |
| O'malley | 104 |
| Olive | 103 |
| Osborn | 97 |
| Oldham | 97 |
| O'callaghan | 97 |
| Oates | 93 |
| Oxford | 92 |
| Olson | 88 |
| Olliver | 82 |
| Omega | 82 |
| October | 82 |
| Ormond | 79 |
| Overberg | 78 |
| Overton | 76 |
| Oliveira | 76 |
| Ogden | 74 |
| O'hara | 74 |
| Overland | 73 |
| O'donoghue | 73 |
| Ong | 69 |
| O'shea | 68 |
| Oaks | 65 |
| Orion | 59 |
| O'neil | 58 |
| O'hagan | 57 |
| Orton | 56 |
| O'keeffe | 56 |
| Oswald | 54 |
| O'grady | 53 |
| Oram | 50 |
| Off | 48 |
| Oxley | 44 |
| Orchard | 44 |
| O'carroll | 43 |
| Oscar | 42 |
| Over | 41 |
| Ohlson | 41 |
| Oak | 40 |
| Oxenham | 40 |
| O'flaherty | 37 |
| Ogilvy | 36 |
| Ora | 35 |
| Overend | 34 |
| Oneill | 32 |
| Ochse | 32 |
| Osmond | 29 |
| Ogier | 29 |