| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| Mabon | - | Welsh, Welsh Mythology | ||
| Mabyn | - | Welsh | ||
| Macsen | - | Welsh | ||
| Madoc | - | Welsh | ||
| Madog | - | Welsh | ||
| Mair | MIER | Welsh | ||
| Mairwen | - | Welsh | ||
| Maldwyn | - | Welsh | ||
| Mallt | - | Welsh | ||
| Marc | MAHRHK (French) | French, Catalan, Welsh | ||
| Mared | - | Welsh | ||
| Maredudd | mah-RE-deeth | Welsh | ||
| Marged | - | Welsh | ||
| Mari (1) | MAH-ree (Finnish), mah-REE (Swedish) | Welsh, Breton, Estonian, Finnish, Hungarian, Swedish, Norwegian, Danish | ||
| Martyn | - | Welsh, Ukrainian |