| Ojinjintka | Woman | Native American - Sioux Names |
| Okal | Unisex | African Names |
| Okalani | Woman | Hawaiian Names |
| Okan | Man | Turkish Names |
| Okapi | Unisex | African Names |
| Oke | Unisex | Hawaiian Names |
| Okena | Unisex | Native American - Blackfoot Names |
| Oki | Woman | Japanese Names |
| Oklahoma | Unisex | Native American - Choctaw Names |
| Okoth | Unisex | African Names |
| Oksana | Woman | Slavic Names |
| Oktyabrina | Woman | Russian Names |
| Ola | Man | Scandinavian Names |
| Olabisi | Unisex | African - Yoruba Names |
| Olaf | Man | Scandinavian Names |
| Olai | Man | Scandinavian Names |
| Olalla | Man | Spanish Names |
| Olaniyi | Woman | African - Nigeria Names |
| Olathe | Woman | Native American Names |
| Olatunde | Man | African - Edo of Nigeria Names |