| O`shay | surname |
| O`shea | surname |
| O~keefe | Descendant of the noble Caoimhghin. |
| O~shay | Descendant of the hawk like man. |
| O~shea | Descendant of the majestic hawk. |
| Obuli | Name of a Hindu God |
| Ojis | Full of vital energy. |
| Om Parkash | The light of divinity. |
| Omish | Lord of the sacred Om. |
| Oneesh | Lord of the mind or soul. |
| Onik | Various, Soldier |
| Onis | One who brings comfort. |
| Olka | A holy or sacred person |
| Ons | Peace and great comfort |
| Onshuda | One who brings great joy. |
| Onsi | One who brings calm and gladness to the heart |
| Oraibia | A person of noble character. |
| Osaf | One who is pure and honest. |
| Omsrikara | The creator of divine fortune. |
| ORNEET | Little eagle ; |
| ORNET | Little eagle ; |
| OUSHAD | A healing medicinal herb. |
| Oachim | God will establish |
| Oakland | Oakland is derived from the Old English words 'oak' and 'land', referring to a wooded area. |
| Obama | One who leans or is bent. |
| Oban | Oban means 'little bay' or 'small inlet' in Gaelic, referring to a coastal town in Scotland. |
| Obed Edom | Servant of Edom; He who serves the edomites |
| Obrecht | Known for his inheritance |
| Ocelotl | Ocelotl means 'beauty' or 'handsome one' in the Nahuatl language, an indigenous Mexican dialect. |
| Ochuko | Ochuko is a Nigerian name meaning 'God's gift' or 'gift from God' in the Urhobo language. |
| Ocie | Polish diminutive form of Oskar, meaning 'little dear' or 'beloved'. |
| OConnor | Wisdom; counsel; strength |
| Octavey | Born as the eighth child. |
| Octaviano | Derived from Latin 'octavus,' meaning eighth, and 'ianus,' a suffix indicating a place or a person. |
| Octavien | Derived from Latin 'octavus,' meaning eighth, possibly referring to birth order or eighth child. |
| Octavo | The eighth born in a family. |
| Odaniyan | Odaniyan is a Sanskrit name meaning 'auspicious' or 'blessed' and is often associated with good fortune. |
| Odern | Modern means being in accordance with the present or the most recent time period. |
| Odilio | One who is wealthy or rich. |
| Odis | Odys means 'traveler' or 'wanderer' in Greek, derived from the word 'odysseia' meaning journey. |