| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| Otho | - | Ancient Roman | ||
| Otieno | - | Eastern African, Luo | ||
| Otmar | - | German, Ancient Germanic | ||
| OttÓ | - | Hungarian, Icelandic | ||
| Ottavia | - | Italian | ||
| Ottaviano | - | Italian | ||
| Ottavio | - | Italian | ||
| Ottilie | o-TEE-lee-ə | German | ||
| Ottmar | - | German | ||
| Otto | AW-to (German), AH-to (English), OT-to (Finnish) | German, Swedish, Norwegian, Danish, Dutch, English, Finnish, Ancient Germanic | ||
| Ottokar | - | German | ||
| Ottomar | - | German | ||
| Ottone | - | Italian | ||
| Ottorino | - | Italian | ||
| Ove | - | Swedish, Norwegian, Danish |