| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| Odoacer | o-do-AY-sər (English) | Ancient Germanic | ||
| Odovacar | o-do-VAY-kər (English) | Ancient Germanic | ||
| Ogden | AWG-dən | English | ||
| Ohannes | - | Armenian | ||
| Oli | AHL-ee | English | ||
| Olive | AHL-iv | English | ||
| Oliver | AHL-ə-vər (English), AW-lee-ver (German), O-lee-ver (Finnish) | English, German, Swedish, Norwegian, Danish, Finnish, Estonian, Serbian, Croatian, Macedonian, Czech | ||
| Olivia | ə-LIV-ee-ə (English), o-LEE-vyah (Italian, Spanish), o-LEE-vee-ah (German), O-lee-vee-ah (Finnish) | English, Italian, Spanish, German, Finnish, Swedish, Norwegian, Danish | ||
| Olivie | o-lee-VEE (French) | French, Czech | ||
| Olivier | o-lee-VYE (French), O-lee-veer (Dutch) | French, Dutch | ||
| Ollie | AHL-ee | English | ||
| Olympe | - | French | ||
| Olympias | - | Ancient Greek | ||
| Olympiodoros | - | Ancient Greek | ||
| Olympos | - | Ancient Greek |