| Milo | | MIE-lo (English) | English, Ancient Germanic | |
| Norbert | | NAWR-bert (German, Polish), NAWR-bərt (English, Dutch) | German, English, Dutch, French, Hungarian, Polish, Ancient Germanic | |
| Norman | | NAWR-mən (English) | English, Ancient Germanic | |
| Oda | | O-dah (German) | German, Ancient Germanic | |
| Odalric | | - | Ancient Germanic | |
| Odila | | - | Ancient Germanic | |
| Odilia | | - | Ancient Germanic | |
| Odilo | | - | Ancient Germanic | |
| Odo | | - | Ancient Germanic | |
| Odoacer | | o-do-AY-sər (English) | Ancient Germanic | |
| Odovacar | | o-do-VAY-kər (English) | Ancient Germanic | |
| Ortwin | | AWRT-veen (German) | German, Ancient Germanic | |
| Othmar | | - | German, Czech, Ancient Germanic | |
| Otmar | | - | German, Ancient Germanic | |
| Otto | | AW-to (German), AH-to (English), OT-to (Finnish) | German, Swedish, Norwegian, Danish, Dutch, English, Finnish, Ancient Germanic | |