| Location | States or Territories | Abbreviation | Postcode |
|---|---|---|---|
| Oak Park | Victoria | VIC | 3046 |
| Oaklands Junction | Victoria | VIC | 3063 |
| Oakleigh | Victoria | VIC | 3166 |
| Oakleigh East | Victoria | VIC | 3166 |
| Oakleigh South | Victoria | VIC | 3167 |
| Oakvale | Victoria | VIC | 3540 |
| Ocean Grange | Victoria | VIC | 3880 |
| Ocean Grove | Victoria | VIC | 3226 |
| Officer | Victoria | VIC | 3809 |
| Officer South | Victoria | VIC | 3809 |
| Old Tallangatta | Victoria | VIC | 3701 |
| Olinda | Victoria | VIC | 3788 |
| Ombersley | Victoria | VIC | 3241 |
| Omeo | Victoria | VIC | 3898 |
| Omeo Valley | Victoria | VIC | 3898 |
| Ondit | Victoria | VIC | 3249 |
| Orbost | Victoria | VIC | 3888 |
| Orford | Victoria | VIC | 3284 |
| Ormond | Victoria | VIC | 3204 |
| Orrvale | Victoria | VIC | 3631 |
