| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| Obadiah | o-bə-DIE-ə (English) | Biblical | ||
| Obed | O-bed (English) | Biblical, Biblical Latin, Biblical Greek | ||
| Obi | - | Western African, Igbo | ||
| OcÉAne | o-se-AHN | French | ||
| Ochieng | - | Eastern African, Luo | ||
| 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 | ||
| Oded | - | Biblical | ||
| Odette | o-DET | French | ||
| Odhiambo | - | Eastern African, Luo |