| Boy Name | Meaning |
| Oaghavanth | Monarch; King |
| Oak | Place Name; From the Oak Tree Meadow |
| Oakden | From the oak tree valley |
| Oakes | From the oak |
| Oaklee | From the Oak Tree Meadow |
| Oakleigh | From the Oak Tree Meadow |
| Oakley | From the oak - tree meadow |
| Oakly | From the Oak Tree Meadow |
| Oaks | Place Name; Near the Oak Trees |
| Oangaran | God Muruga |
| Oasis | Beautiful; Desert |
| Oates | Variant of Odo: Wealth. |
| OBA | king |
| Obadiah | Serves God |
| OBADIAH, | serves God |
| Obaid | Small Slave |
| Obal | Inconvenience of old age. |
| Obalesh | Lord Shiva |
| Obaleshwar | Shiva |
| OBASI | Ibo of Nigeria name meaning "in honor of the supreme God." |
| Obayana | king of fire |
| Obed | A servant; workman |
| Obed-Edom | Servant of Edom, He who serves the edomites |
| Obediah | Serves God |
| Obelix | pillar of strength |
| Obhihas | Belongs to World |
| OBI | Ibo of Nigeria name meaning "heart." |
| Obiajulu | the heart is consoled |
| OBIAREUS | myth name (a Titan) |
| Obie | The Quality of Being Obedient; Servant of God |
| OBIKE | Ibo of Nigeria name meaning "a strong household." |
| Obil | That weeps, who deserves to be bewailed. |
| Oboth | Dragons, fathers, desires' |
| Obrian | Surname. |
| Obrien | Surname. |
| Occhar | Pickle; Brave; Hero; Hunter |
| Occhav | Love |
| OCEANUS | myth name (father of the Oceanids) |
| Ocelfa | From the high plain |
| Ochaar | Pronunciation |