1,362 results
| O'brien | 6431 |
| Oliver | 3923 |
| O'connor | 3615 |
| Owen | 3095 |
| O'neill | 3038 |
| Osborne | 3002 |
| Obrien | 2410 |
| O'sullivan | 1970 |
| O'donnell | 1784 |
| Olsen | 1759 |
| Owens | 1596 |
| O'connell | 1440 |
| Orr | 1396 |
| Ong | 1214 |
| O'reilly | 1128 |
| O'shea | 1030 |
| Oakley | 1010 |
| Oates | 1001 |
| Oconnor | 983 |
| Oneill | 944 |
| O'leary | 804 |
| Osborn | 729 |
| O'neil | 702 |
| O'callaghan | 676 |
| Orchard | 668 |
| Ogden | 660 |
| Osman | 645 |
| Oldfield | 630 |
| O'grady | 617 |
| O'hara | 613 |
| Oakes | 596 |
| O'keeffe | 566 |
| Odonnell | 565 |
| Ogilvie | 557 |
| O'malley | 533 |
| Otto | 524 |
| Osullivan | 494 |
| Olive | 491 |
| Oxley | 438 |
| Oconnell | 419 |
| Oldham | 416 |
| Osmond | 392 |
| O'donoghue | 383 |
| Oliveira | 381 |
| Overton | 378 |
| Omar | 374 |
| Oswald | 373 |
| Olsson | 369 |
| Odgers | 346 |
| Oreilly | 346 |
| Oshea | 336 |
| Okeefe | 331 |
| Olson | 329 |
| Ooi | 295 |
| Opie | 283 |
| Oleary | 271 |
| Obst | 269 |
| Ormsby | 258 |
| Otoole | 246 |
| Ogle | 239 |
| Oneil | 238 |
| O'hare | 237 |
| Ohara | 235 |
| Orlando | 222 |
| Organ | 221 |
| Osbourne | 217 |
| Orton | 215 |
| Ovens | 214 |
| Ord | 207 |
| Ortiz | 205 |
| Orourke | 199 |
| Oram | 197 |
| Ohalloran | 192 |
| Olds | 185 |
| Ogrady | 181 |