| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| Oskar | AWS-kahr (German, Polish) | Swedish, Norwegian, Danish, German, Polish | ||
| Oswald | AHZ-wawld (English), AWS-vahlt (German) | English, German, Anglo-Saxon | ||
| Othmar | - | German, Czech, Ancient Germanic | ||
| Otmar | - | German, Ancient Germanic | ||
| 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 |