| Name | Meaning | Gender | Origin |
|---|
| Mischief | One that causes minor trouble or disturbances | Unisex | English |
| Mister | | Unisex | Hebrew |
| Mittens | | Unisex | Hebrew |
| Mitzi | Uncertain, maybe bitter | Unisex | Hebrew |
| Mitzy | | Unisex | Hebrew |
| Mo | Moor | Unisex | Latin |
| Mocha | Coffee of high quality. | Unisex | English |
| Mojo | Good luck charm. | Unisex | English |
| Monster | A creature of frightening appearance | Unisex | English |
| Montana | Mountainous | Unisex | Latin |
| Montgomery | Gomeric's hill | Male | French |
| Monty | Gomeric's hill | Male | French |
| Moose | Largest member of the deer family. Moose have heavy brown bodies with humped shoulders and broad antlers. | Unisex | English |
| Moses | Drawn out of the water | Male | Hebrew |
| Mouse | A small rodent with a long tail and small rounded ears. | Unisex | English |
| Muffin | A small cup shaped cake | Unisex | English |
| Muffy | | Unisex | Hebrew |
| Munchkin | A very small elflike person. | Unisex | English |
| Murphy | Sea warrior | Male | Gaelic |
| Nana | Grace | Unisex | Hebrew |
| Napoleon | Sons of the mist, a race of dwarves | Male | Germanic |
| Nemo | No one | Male | Latin |
| Nero | Stern | Male | Latin |
| Newt | New settlement, new enclosure | Unisex | English |
| Newton | New settlement, new enclosure | Male | English |
| Nibbles | | Unisex | Hebrew |
| Nick | Victory of the people | Male | Greek |
| Nicky | Victory of the people | Unisex | Greek |
| Nico | Victory of the people | Male | Greek |
| Niko | Victory of the people | Male | Greek |