| City | 2026 Pop. ↓ |
|---|---|
| Madrid | 3,543,630 |
| Malaga | 603,540 |
| Murcia | 483,780 |
| Mostoles | 215,923 |
| Marbella | 162,771 |
| Mataro | 132,234 |
| Mijas | 97,250 |
| Melilla | 86,708 |
| Manresa | 81,591 |
| Molina de Segura | 79,656 |
| Majadahonda | 73,963 |
| Merida | 60,364 |
| Motril | 60,164 |
| Mollet del Valles | 53,307 |