| Oonitejas | One who radiates divine light. |
| Oordhavaketu | One with an elevated banner. |
| Oordhvasaayin | One who rests in high places. |
| Oorethva | A person who is rising upwards. |
| Oorjasthambha | A pillar of immense strength. |
| Oorjasvin | One who is full of vital energy. |
| Oorjavaha | One who possesses great energy. |
| Oorna | Name of Yaksha; name of a son of Dhritarashtra |
| Oornedara | One who wears a wool garment. |
| Oorva | Derived from the earth or soil. |
| Orangelo | Orange and angel, a combination name suggesting a bright and heavenly personality. |
| Orazio | Hour; time; period |
| ORourke | Derived from the Gaelic surname 'Ó Ruairc,' meaning 'descendant of Ruairc,' a personal name meaning 'red king.' |
| Orra | Light or illumination of spirit. |
| Orush | A name meaning light or brilliance. |
| Osamaa | One who is a lion or a protector. |
| Osul | Figuratively principles; essentials |
| Osweldo | A ruler with divine power or might. |
| Othmane | A name meaning baby bustard bird. |
| Ouchitya | One who possesses great energy. |
| Oujasya | One who is full of vital energy. |
| Ouraj | Born from the sun or light |
| Outathya | One who is highly learned |
| Ovadia | Ovadia is a Hebrew name meaning 'servant of God' or 'God's servant'. |
| Owenn | A well born man |
| Oysin | A small deer or fawn |
| Ozaafar | One who brings victory |
| Ozair | A prophet; Ezra in English |
| Ozymandias | King of Kings, ruler of kings, a title given to the Egyptian pharaoh Ramses II. |
| Obataiye | King of the world |
| Obawole | the king enters the house |
| Odongo | born after twins |
| Ogbonna | The image of his father |
| Ojore | A warrior born during wartime. |
| Okafor | born on Afor market day |
| Okanlawon | son born after several girls |
| Okechuku | Gods own gift to the family. |
| Okeke | born on the market day |
| Okwayi | referring to the Almighty |
| Oladele | Honours, Wealth Arrive at Home |