Paradiplomacy is a worldwide phenomenon. Sub-state governments (SSG) are increasingly conducting international relations, and the activity can impact foreign policy decision making and implementation and states’ interactions in the international system. Ten countries, representing all the regions of the world, were analyzed using the model, first presenting the institutional configuration, then the most important political, economic and social variables, and then analyzing the legal framework, coordination and international actions of SSGs. The relevance of international relations of sub-state governments for foreign policy decision making and implementation is negligible in exclusive cases, limited in consultative and complementary cases and increasingly important in inclusive cases, especially in those areas where SSGs have constitutional powers. Belgium is the only case in which SSGs participate in foreign policy definition and implementation in equal terms with the federal government, in those areas in which the former has constitutional powers.