| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 681 | MacArthur | Gaelic | Son of Arthur. | M | |
| 682 | MacArtuir | Gaelic | Son of Arthur. | M | |
| 683 | MacLean | Gaelic | Son of the handsome man. | M | |
| 684 | MacNab | Gaelic | Son of the Father or Abbott. | M | |
| 685 | Mairearad | Gaelic | Pearl. | F | |
| 686 | Mairghread | Gaelic | Pearl. | F | |
| 687 | Mairi | Gaelic | Bitter. | F | |
| 688 | Malcolm | Gaelic | Servant/disciple of Columba. Famous Bearers: Conductor Sir Malcolm Sargent and U.S. black militant Malcolm X (Malcolm Little). | M | |
| 689 | Malise | Gaelic | Servant of Jesus. | M | |
| 690 | Maloney | Gaelic | Devoted to God. | M | |
| 691 | Malvin | Gaelic | Polished chief. | M | |
| 692 | Malvina | Gaelic | Smooth brow. | F | |
| 693 | Mannis | Gaelic | Great. | M | |
| 694 | Manus | Gaelic | Great. | M | |
| 695 | Maoldhomhnaigh | Gaelic | Devoted to God. | M | |
| 696 | Maolmin | Gaelic | Polished chief. | F | |
| 697 | Maolmin | Gaelic | Polished chief. | M | |
| 698 | Maoltuile | Gaelic | Quiet. | M | |
| 699 | Marcus | Gaelic | Hammer. | M | |
| 700 | Marsali | Gaelic | Pearl. | F | |