| Source | UN (World Population Prospects 2019) |
| Date | 09 Sep 2021 |
| Rank | City | Population | Share (%) | Change | ||
|---|---|---|---|---|---|---|
| 2020 | 2021 | Population | (%) | |||
| 1 | Madrid | 6,617,513 | 6,668,865 | 14.3 | 51,352 | 0.78 |
| 2 | Barcelona | 5,585,556 | 5,624,498 | 12.0 | 38,942 | 0.70 |
| 3 | Valencia | 833,724 | 835,341 | 1.79 | 1,617 | 0.19 |
| 4 | Zaragoza | 730,828 | 733,825 | 1.57 | 2,997 | 0.41 |
| 5 | Sevilla | 703,790 | 702,386 | 1.50 | -1,404 | -0.20 |
| 6 | Malaga | 590,032 | 591,091 | 1.26 | 1,059 | 0.18 |
| 7 | Murcia | 499,783 | 504,491 | 1.08 | 4,708 | 0.94 |
| 8 | Palma | 467,005 | 472,140 | 1.01 | 5,135 | 1.10 |
| 9 | Las Palmas Gran Canaria | 401,900 | 402,732 | 0.862 | 832 | 0.21 |
| 10 | Alicante | 369,758 | 372,665 | 0.797 | 2,907 | 0.79 |
| 11 | Bilbao | 349,633 | 348,518 | 0.746 | -1,115 | -0.32 |
| 12 | Cordoba | 343,719 | 344,214 | 0.736 | 495 | 0.14 |
| 13 | Vigo | 306,853 | 307,056 | 0.657 | 203 | 0.07 |
| 14 | Valladolid | 305,047 | 303,613 | 0.650 | -1,434 | -0.47 |