This is a list of the largest metropolitan areas in Spain by population.

Estimates are from the following sources:

The figures differ between the reports due to the difference in survey dates and differences in methodology. For example, ESPON considers Oviedo–Gijón–Avilés as a single FUA, while Urban Audit has separate LUZs for Oviedo and Gijón. Similarly, Vilanova i la Geltrú is included in Barcelona metropolitan area by ESPON, but as a separate conurbation by Ruiz.