| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| OĽGA | - | Slovak | ||
| OANA | WAH-nah | Romanian | ||
| OANEZ | - | Breton | ||
| OBDULIA | - | Spanish | ||
| OCÉANE | o-se-AHN | French | ||
| OCTÁVIA | - | Portuguese | ||
| Octavia | [ɔk'teiviə] | |||
| OCTAVIA | ahk-TAYV-ee-ə (English) | English, Spanish, Ancient Roman | ||
| ODA | O-dah (German) | German, Ancient Germanic | ||
| ODALYS | - | Spanish | ||
| ODARKA | - | Ukrainian | ||
| ODELIA | - | English | ||
| ODESSA | - | Various | ||
| ODETA | - | Lithuanian | ||
| ODETTA | - | English (Rare) |