| Name | Meanings | Gender | Origin |
|---|---|---|---|
| Oakes | from the oak-tree grove | Boy | English |
| Oakley | Field of Oak Trees | Boy | Anglo-Saxon |
| Obert | Otter | Boy | German |
| Octavio | The Eighth | Boy | Latin |
| Odin | head god in Norse mythology | Boy | Scandinavian |
| Odon | wealthy protector | Boy | Hungarian |
| Odysseus | Full of Wrath | Boy | |
| Olaf | Ancestor (Dan) | Boy | Scandinavian |
| Olin | Holly | Boy | Scandinavian |
| Oliver | an olive | Boy | Latin |
| Omar | life | Boy | Arabic |
| Oran | Green | Boy | Gaelic |
| Oren | ash-tree | Boy | Hebrew |
| Oringo | He Who Likes the Hunt | Boy | African |
| Orion | son of fire, the hunter | Boy | Greek |
| Orlando | Land of Gold | Boy | German |
| Orman | spear man | Boy | English |
| Ormand | Serpent | Boy | |
| Orsen | Form of ORSON. A Bear | Boy | |
| Orsin | Form of ORSON. A Bear | Boy | |
| Orson | A Bear | Boy | Latin |
| Orville | Golden City | Boy | Anglo-Saxon |
| Osborne | Soldier of God | Boy | |
| Oscar | Divine Strength | Boy | Scandinavian |
| Oskar | Form of OSCAR. Divine Strength | Boy | Scandinavian |
| Osma | Protective Hero | Boy | |
| Oswald | God of the Forest | Boy | English |
| Othello | Prosperous | Boy | |
| Otis | One Who Hears Well | Boy | Greek |
| Otto | Form of OTHELLO. Prosperous | Boy | Teutonic |
| Ovid | Egg Shaped | Boy | Latin |
| Owen | Form of EVAN. young warrior | Boy | Celtic |
| Oz | Strength | Boy | |
| Ozzie | Form of OZ. Strength | Boy | Hebrew |