| Greek baby names begining from O |
| Obelia |
 | Pointed pillar. |
| Obelie |
| Pointed pillar. |
| Obiareus |
 | A Titan. |
| Oceana |
| Form of Oceanus. In Greek mythology Oceanus was a Titan father of rivers and water nymphs. |
| Oceanus |
| Father of the Oceanids. |
| Ocnus |
| Incompetent. |
| Ocypete |
| A Harpy. |
| Odele |
| Harmonious. |
| Odelet |
| Little singer. |
| Odelette |
| Little singer. |
| Odelle |
| Harmonious. |
| Odessa |
| Wrathful. |
| Odysseia |
| Wrathful. |
| Odysseus |
| Wrathful. |
| Oedipus |
| Swollen foot. |
| Oeneus |
| King of Calydon. |
| Oenomaus |
| Son of Ares. |
| Oenone |
| Lover of Paris. |
| Oighrig |
 | Well spoken. |
| Oleisia |
| Protector of man. |
| Olena |
| Light. |
| Oles |
| Defender of man. |
| Olexa |
| Defender of mankind. Feminine of Alexander. |
| Olina |
| Light. |
| Olympe |
| From Olympus. |
| Olympia |
| From the home of the gods (Olympus). |
| Omphale |
| A queen of Lydia. |
| Onella |
| Light. |
| Ophelia |
| Help. Serpentine. In Shakespeare's 'Hamlet', Ophelia was the lover of Hamlet who went insane as a result of his irrational behavior. |
| Ophelie |
| Wisdom. |
| Ophion |
| A serpent. |
| Orea |
| From the mountain. |
| Oreias |
| From the mountain. |
| Oreste |
| From the mountain. |
| Orestes |
| From the mountain. |
| Oria |
| From the mountain. |
| Orion |
| Rising in the sky; dawning. Mythological Orion was a mighty hunter and son of Poseidon. The constellation Orion contains three conspicuous stars. |
| Orpheus |
| Son of Apollo. |
| Orthros |
| Guardian of Geryon. |
| Ortygia |
| Calypso's island. |
| Otis |
| Keen of hearing. |
| Otos |
| Keen of hearing. |
| Otus |
| Keen of hearing. |
| Owain |
| Variant of Eugene: Well-born. Famous bearer: Prince Eugene of Savoy; American playwright Eugene O'Neill. |
| Owen |
| Variant of Eugene: Well-born. Famous bearer: Prince Eugene of Savoy. |
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