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.
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.