| Next | Last |
| NAME | MEANING | GENDER | ORIGIN |
| OAKES | Beside the Oak Trees | E� | English� |
| OAKLEY | Field of Oak Trees | E� | English� |
| OBEDIENCE | To Obey | E� | American� |
| OBELIA | Needle | F� | Greek� |
| OBERON | Bear Heart | E� | German� |
| OBERT | Wealthy | E� | German� |
| OCEAN | Sea | F� | Greek� |
| OCEANA | From the Sea | F� | Greek� |
| OCTAVIA | The Eighth | F� | Latin� |
| OCTAVIO | The Eighth | M� | Latin� |
| OCTAVIOUS | Eighth | M� | Latin� |
| OCTAVIUS | The Eighth | M� | Greek� |
| OCTOBER | Born in October | E� | American� |
| ODAKOTA | Friend | M� | Native American� |
| ODED | Strong | M� | Hebrew� |
| ODEDA | Strong | F� | Hebrew� |
| ODELE | Wealthy, Melody | F� | Greek� |
| ODELIA | I will praise God | F� | Greek� |
| ODELL | Otter | E� | English� |
| ODESSA | The Odyssey | F� | Latin� |
| ODETTA | Ode | F� | French� |
| ODETTE | Ode, Melodic | F� | French� |
| ODIN | Supreme God | E� | Scandinavian� |
| ODINA | Mountain | F� | Latin� |
| ODYSSEUS | Full of Wrath | M� | Greek� |
| OFIRA | Gold | F� | Hebrew� |
| OGDEN | From the Valley of Oaks | M� | English� |
| OHANZEE | Shadow | M� | Native American� |
| OHIO | Large River | E� | Native American� |
| OIHANE | From the Forest | F� | Spanish� |
| OISTIN | Venerable | E� | Latin� |
| OJAL | Vision | F� | Sanskrit (India)� |
| OJAS | Strong One | M� | Sanskrit (India)� |
| OKAL | To Cross | E� | African� |
| OKALANI | Heaven | F� | Hawaiian� |
| OKAPI | Animal with Long Neck | E� | African� |
| OKE | Form of OSCAR | E� | Hawaiian� |
| OKI | Ocean Centered | F� | Japanese� |
| OKLAHOMA | Red People | E� | Native American� |
| OKOTH | Born when it was Raining | E� | African� |
| OKSANA | God is With Us | F� | Slavic� |
| OLAF | Ancestor | M� | Scandinavian� |
| OLATHE | Lovely, Beautiful | F� | Native American� |
| OLE | Ancestor | M� | Scandinavian� |
| OLEG | Sacred | M� | Slavic� |
| Next | Last |