| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| OŽBalt | - | Slovene | ||
| OŽBej | - | Slovene | ||
| OcÉAne | o-se-AHN | French | ||
| Ocean | O-shən | English (Rare) | ||
| Octave | - | French | ||
| 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 | ||
| Ode | - | Medieval English | ||
| Odelia | - | English | ||
| Odell | o-DEL | English | ||
| Odetta | - | English (Rare) |