| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| OWAIN | O-wien (Welsh, Welsh Mythology) | Welsh, Welsh Mythology, Arthurian Romance | ||
| Owen | ['əuin] | |||
| OWEN (1) | O-ən (English) | Welsh, English | ||
| OWEN (2) | - | Irish | ||
| OWENA | - | Welsh | ||
| OXANA | - | Ukrainian, Russian | ||
| OYIBO | - | Western African, Urhobo | ||
| OYUNCHIMEG | - | Mongolian | ||
| OZ (1) | AHZ | English | ||
| OZ (2) | - | Hebrew | ||
| OZAN | - | Turkish | ||
| OZAZIAS | - | Biblical Greek | ||
| OZI | - | Biblical Latin, Biblical Greek | ||
| OZIAS | - | Biblical Latin, Biblical Greek | ||
| OZIEL | - | Biblical Greek |