| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| OĽGA | - | Slovak | ||
| OŽBALT | - | Slovene | ||
| OŽBEJ | - | Slovene | ||
| Oakes | [əukəz] | |||
| Oakley | ['əukli] | |||
| OANA | WAH-nah | Romanian | ||
| OANEZ | - | Breton | ||
| OBADIAH | o-bə-DIE-ə (English) | Biblical | ||
| OBDULIA | - | Spanish | ||
| OBED | O-bed (English) | Biblical, Biblical Latin, Biblical Greek | ||
| OBERON | O-bər-ahn (English) | Literature | ||
| OBI | - | Western African, Igbo | ||
| OBRAD | - | Serbian | ||
| OCÉANE | o-se-AHN | French | ||
| OCEAN | O-shən | English (Rare) |