| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| OCEAN | O-shən | English (Rare) | ||
| ODALIS | - | Spanish | ||
| ODELL | o-DEL | English | ||
| OFIR | - | Hebrew, Biblical Hebrew | ||
| OFRA | - | Hebrew | ||
| OGHENEKARO | - | Western African, Urhobo | ||
| OGHENEKEVWE | - | Western African, Urhobo | ||
| OGHENERO | - | Western African, Urhobo | ||
| Ollie | ['ɔli] | |||
| OLLIE | AHL-ee | English | ||
| OLUCHI | - | Western African, Igbo | ||
| OLUFUNKE | - | Western African, Yoruba | ||
| OLUFUNMILAYO | o-loo-foo-mee-LIE-o | Western African, Yoruba | ||
| OLUFUNMILOLA | - | Western African, Yoruba | ||
| OLUWAFUNMILAYO | - | Western African, Yoruba |