| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| Ormazd | OR-mazd | Persian Mythology | ||
| Ornella | - | Italian | ||
| Orsina | - | Italian | ||
| Orsino | - | Italian | ||
| Orso | - | Italian | ||
| Orsola | OR-so-lah | Italian | ||
| Orsolya | - | Hungarian | ||
| Ortrun | AWRT-roon | German | ||
| Ortwin | AWRT-veen (German) | German, Ancient Germanic | ||
| Osamu | o-sah-moo | Japanese | ||
| Osanna | - | Italian (Rare) | ||
| Osbeorn | - | Anglo-Saxon | ||
| Osberht | - | Anglo-Saxon | ||
| Oscar | AHS-kər (English) | English, Irish, Portuguese (Brazilian), Italian, Swedish, Norwegian, Danish, Dutch, French, Irish My | ||
| Osgar | - | Anglo-Saxon |