| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| OlivÉR | O-lee-vayr | Hungarian | ||
| Ona (1) | - | Lithuanian | ||
| Onisimu | - | Old Church Slavic | ||
| OrbÁN | - | Hungarian | ||
| Orsolya | - | Hungarian | ||
| OszkÁR | - | Hungarian | ||
| OttÓ | - | Hungarian, Icelandic | ||
| Owain | O-wien (Welsh, Welsh Mythology) | Welsh, Welsh Mythology, Arthurian Romance | ||
| PÁL | PAHL | Hungarian | ||
| PÉTer | PAY-ter | Hungarian | ||
| Panna | PAWN-naw | Hungarian | ||
| Panni | PAWN-nee | Hungarian | ||
| Passang | - | Tibetan, Bhutanese | ||
| Patigul | - | Uyghur | ||
| Patime | - | Uyghur |