| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 761 | Nilos | Greek | People's victory. | M | |
| 762 | Nils | Greek | People's victory. | M | |
| 763 | Niocol | Greek | People's victory. | M | |
| 764 | Niocole | Greek | People's victory. | M | |
| 765 | Nisus | Greek | Father of Scylla. | M | |
| 766 | Notus | Greek | The south wind. | M | |
| 767 | Obiareus | Greek | A Titan. | M | |
| 768 | Oceanus | Greek | Father of the Oceanids. | M | |
| 769 | Ocnus | Greek | Incompetent. | M | |
| 770 | Odysseus | Greek | Wrathful. | M | |
| 771 | Oedipus | Greek | Swollen foot. | M | |
| 772 | Oeneus | Greek | King of Calydon. | M | |
| 773 | Oenomaus | Greek | Son of Ares. | M | |
| 774 | Oighrig | Greek | Well spoken. | M | |
| 775 | Oles | Greek | Defender of man. | M | |
| 776 | Ophion | Greek | A serpent. | M | |
| 777 | Oreias | Greek | From the mountain. | M | |
| 778 | Oreste | Greek | From the mountain. | M | |
| 779 | Orestes | Greek | From the mountain. | M | |
| 780 | Orion | Greek | Rising in the sky; dawning. Mythological Orion was a mighty hunter and son of Poseidon. The constellation Orion contains three conspicuous stars. | M | |