| Name | Meaning | Gender | Origin |
|---|
| Marbles | Irregularly coloured rock. Balls usually made of glass used as a children's game. | Male | |
| Mario | bitter, king-ruler | Male | Italian |
| Maximus | greatest | Male | Latin |
| Maxwell | Capable
| Male | Scottish |
| Maynard | Firm
| Male | |
| Mayo | yew-tree plain | Male | Irish |
| Megaton | | Male | |
| Mellow | | Unisex | Hebrew |
| Merlin | Character on Chocolate Frog card.
| Male | Welsh |
| Merlot | | Male | |
| Mickey | Abbreviation of Michael and Micah Who is like God?
| Male | English |
| Midas | | Unisex | Hebrew |
| Midget | A small or miniature version | Unisex | |
| Mikeal | | Male | |
| Milo | Merciful.
| Male | Latinized |
| Milo | Merciful.
| Male | Latinized |
| Mister | | Male | |
| Mojo | Good luck charm. | Unisex | |
| Monty | From Montgomer - The mountain hunter. | Male | English |
| Moppet | A young child. | Unisex | |
| Mork And Mindy | | Unisex | Hebrew |
| Mouse | A small rodent with a long tail and small rounded ears. | Unisex | |
| Muffin | A small cup shaped cake | Unisex | |
| Munchkin | A very small elflike person. | Unisex | |
| Napoleon | Hound Dog from the AristoCats
| Male | Greek |