| Maximus | | - | Ancient Roman | |
| Medraut | | - | Welsh Mythology, Arthurian Romance | |
| Medrod | | - | Welsh Mythology, Arthurian Romance | |
| Melania | | me-LAHN-yah (Polish) | Italian, Spanish, Polish, Late Roman | |
| Mercurius | | - | Roman Mythology | |
| Mercury | | MURK-yə-ree (English) | Roman Mythology (Anglicized) | |
| Merlin | | MUR-lin (English) | Arthurian Romance, English | |
| MihĂIȚĂ | | - | Romanian | |
| Mihaela | | mee-hah-YE-lah (Romanian), mee-HAH-el-ah (Croatian) | Romanian, Slovene, Croatian, Macedonian | |
| Mihai | | - | Romanian | |
| Mihail | | - | Romanian, Bulgarian, Macedonian, Greek | |
| Minerva | | mi-NUR-və (English) | Roman Mythology, English | |
| Minodora | | - | Romanian | |
| Mircea | | - | Romanian | |
| Mirela | | - | Romanian, Croatian | |