| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| Owain | O-wien (Welsh, Welsh Mythology) | Welsh, Welsh Mythology, Arthurian Romance | ||
| Oxana | - | Ukrainian, Russian | ||
| Oyibo | - | Western African, Urhobo | ||
| Oyunchimeg | - | Mongolian | ||
| Ozazias | - | Biblical Greek | ||
| Ozi | - | Biblical Latin, Biblical Greek | ||
| Ozias | - | Biblical Latin, Biblical Greek | ||
| Oziel | - | Biblical Greek | ||
| Ozihel | - | Biblical Latin |