| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| Oroitz | - | Basque | ||
| Orpha | AWR-fə (English) | Biblical, English | ||
| Orrell | - | English (Rare) | ||
| Orrin | - | Irish | ||
| Orson | AWR-sən | English | ||
| Ortzi | - | Basque | ||
| Orval | AWR-vəl | English | ||
| Orvar | - | Swedish, Norse Mythology | ||
| Orville | AWR-vil | English | ||
| Orvokki | OR-vok-kee | Finnish | ||
| Osamu | o-sah-moo | Japanese | ||
| Osane | - | Basque | ||
| Osbeorn | - | Anglo-Saxon | ||
| Osberht | - | Anglo-Saxon | ||
| Osbert | AHZ-bərt | English (Rare) |