| Mahthildis | | - | Ancient Germanic | |
| Manno | | - | Ancient Germanic | |
| Markos | | - | Greek, Ancient Greek, Biblical Greek | |
| Mathilda | | mə-TIL-də (English, Swedish) | English, Swedish, Ancient Germanic | |
| Meginfrid | | - | Ancient Germanic | |
| Meginhard | | - | Ancient Germanic | |
| Meginrat | | - | Ancient Germanic | |
| Meino | | MIE-no (German, Dutch) | German, Dutch, Ancient Germanic | |
| Meinrad | | MIEN-raht (German) | German, Ancient Germanic | |
| Melanthios | | - | Greek Mythology, Ancient Greek | |
| Melissa | | mə-LIS-ə (English) | English, Dutch, Ancient Greek, Greek Mythology | |
| Meliton | | - | Ancient Greek, Georgian | |
| Melitta | | me-LI-tah (German) | Ancient Greek, German | |
| Menodora | | - | Ancient Greek | |
| Methodios | | - | Ancient Greek | |