The Oxford Handbook of Comparative Regionalism – the first of its kind – offers a systematic and wide-ranging survey of the scholarship on regionalism, regionalization, and regional governance. Unpacking the major debates, leading authors of the field synthesize the state of the art, provide a guide to the comparative study of regionalism, and identify future avenues of research. Twenty-seven chapters review the theoretical and empirical scholarship with regard to the emergence of regionalism, the institutional design of regional organizations and issue-specific governance, as well as the effects of regionalism and its relationship with processes of regionalization. The authors explore theories of cooperation, integration, and diffusion explaining the rise and the different forms of regionalism. The handbook also discusses the state of the art on the world regions: North America, Latin America, Europe, Eurasia, Asia, North Africa and the Middle East, and Sub-Saharan Africa. Various chapters survey the literature on regional governance in major issue areas such as security and peace, trade and finance, environment, migration, social and gender policies, as well as democracy and human rights. Finally, the handbook engages in cross-regional comparisons with regard to institutional design, dispute settlement, identities and communities, legitimacy and democracy, as well as inter- and transregionalism.