The following is a list of ecoregions in Mexico as identified by the World Wide Fund for Nature (WWF). A different system of ecoregional analysis is used by the Commission for Environmental Cooperation, a trilateral body linking Mexican, Canadian and United States environmental regime.

Terrestrial ecoregions

The terrestrial ecoregions of Mexico span two biogeographic realms - the Nearctic and Neotropic - which together constitute the entire biogeography of the Americas. Veracruz is the most biodiverse state with 10 ecoregions across 5 biomes and 2 realms. Chiapas comes in a close second with 10 ecoregions across 4 biomes in the same realm. By contrast, Morelos is the least biodiverse state with just 2 ecoregions.

Freshwater ecoregions

Baja California Complex

Colorado River Complex

Sinaloan Coastal Complex

Rio Bravo Complex

Lerma/Santiago Complex

Rio Panuco Complex

Balsas Complex

Pacific Central Complex

Atlantic Central Complex

Marine ecoregions

Warm Temperate Northeast Pacific

Tropical East Pacific

Warm Temperate Northwest Atlantic

Tropical Northwestern Atlantic