| Mercedes | | mer-THE-dhes (Spanish), mer-SE-dhes (Latin American Spanish) | Spanish | |
| Merche | | MER-che | Spanish | |
| Micaela | | - | Italian, Spanish, Portuguese | |
| Miguel | | mee-GEL | Spanish, Portuguese | |
| Miguela | | - | Spanish, Portuguese | |
| Miguelangel | | mee-gel-AHN-khel | Spanish | |
| Miguelito | | - | Spanish, Portuguese | |
| Milagros | | mee-LAH-gros | Spanish | |
| Mireia | | mee-RE-yə (Catalan) | Catalan, Spanish | |
| Mireya | | - | Spanish | |
| Mirta | | - | Spanish, Italian, Croatian | |
| Modesta | | mo-DHE-stah (Spanish) | Spanish, Late Roman | |
| Modesto | | mo-DHE-sto (Spanish, Italian) | Spanish, Italian, Portuguese | |
| MoisÉS | | moi-SES (Spanish) | Spanish, Portuguese | |