Research on the implementation of social policy is scant compared to research on other policy stages. Reasons like the lack of the necessary time and resources to conduct implementation research explains such gap. Yet, without research on implementation, it is impossible to reach comprehensive, deep and accurate understandings of the effects of public interventions on the welfare of the population. This article introduces the special issue on the dynamics of social policy implementation in Latin America and Southern Europe, prepared with the aim of addressing the gap and contributing to the current research on the topic. The two regions include countries with social policies and welfare regimes that share several historical, institutional and political contexts and legacies, and provide critical cases to test existing theories and models of public policy implementation. The special issue consists of nine articles that cover eight case studies from Argentina, Brazil, Italy, Peru and Spain, plus an article that provides an overview of current implementation trends in the two regions. The comparison of findings from the case studies reveals significant insights on social policy implementation, like a positive effect of the discretion that street-level bureaucrats exert in their daily activities to compensate for weak formal institutions and limited resources, and the opportunities created for the improvement of implementation outcomes by the incorporation of civil society actors in co-production activities.
