| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| Octavia | ahk-TAYV-ee-ə (English) | English, Spanish, Ancient Roman | ||
| Octavianus | - | Ancient Roman | ||
| Octavius | ahk-TAYV-ee-əs (English) | Ancient Roman | ||
| Oda | O-dah (German) | German, Ancient Germanic | ||
| Odalric | - | Ancient Germanic | ||
| Oddr | - | Ancient Scandinavian | ||
| Odila | - | Ancient Germanic | ||
| Odilia | - | Ancient Germanic | ||
| Odilo | - | Ancient Germanic | ||
| Odo | - | Ancient Germanic | ||
| Odoacer | o-do-AY-sər (English) | Ancient Germanic | ||
| Odovacar | o-do-VAY-kər (English) | Ancient Germanic | ||
| Olympias | - | Ancient Greek | ||
| Olympiodoros | - | Ancient Greek | ||
| Olympos | - | Ancient Greek |