This open access edited volume introduces the concept of causal mechanisms to explore new ways of explaining the global dynamics of social policy, and shows that a mechanism-based approach provides several advantages over established approaches for studying social policy. The introductory chapter outlines the mechanism-based approach, which stands out by modularisation and a clear focus on actors. The mechanism-based approach then guides the twelve chapters on social policy developments in different Asian, African, European and Latin American countries. Based on these findings, the concluding chapter provides a structured compilation of causal mechanisms and outlines how a mechanism-based approach can further strengthen research on the global development of social policies, especially in a comparative perspective. The edited volume is highly relevant for social policy scholars from a variety of disciplines, as well as for scholars interested in strengthening explanation in the social sciences.