| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| Omar (1) | - | Arabic, English | ||
| Omar (2) | - | Biblical | ||
| Omobolanle | - | Western African, Yoruba | ||
| Omolara | - | Western African, Yoruba | ||
| Omri | - | Biblical, Hebrew, Biblical Hebrew | ||
| OnÉSime | - | French | ||
| Ona (2) | - | Catalan | ||
| OndŘEj | - | Czech | ||
| Onesimos | - | Ancient Greek, Biblical Greek | ||
| Onesimus | o-NES-i-məs (English) | Biblical, Biblical Latin | ||
| Onesiphoros | - | Ancient Greek, Biblical Greek | ||
| Onesiphorus | - | Biblical, Biblical Latin | ||
| Onfroi | - | Medieval French | ||
| Oni | - | Western African, Yoruba | ||
| Onisimu | - | Old Church Slavic |