Psychologists have historically shown less interest in the outer layers of Bronfenbrenner’s taxonomy (the macro- and exosystem) than in the inner layers. Yet, globalization and migration have underlined the relevance of the outer layers. My thesis is that one specific aspect of the exosystem, immigration policies, is relevant to understanding differences in how immigrants adjust to specific contexts and to understanding why groups coming from the same country of origin fare better in some than in other countries. Comparative studies are one of the up and coming themes in the acculturation field. I first explain two taxonomies of immigration policies, then present findings showing the relevance of these policies, and conclude by describing their opportunities and limitations from a developmental perspective.