This chapter examines sanctions cooperation between regional organizations, the European Union (EU), and the US. It documents the extent of sanctions cooperation and maps patterns across world regions, identifying the extent of interaction in Africa, Asia, the Americas, the Middle East, and Europe. The chapter considers the distinctive character of the EU as a sanctions sender, which imposes sanctions primarily against non-members. It examines three sender types: national sanctions by individual states, regional organizations sanctions, and sanctions of global reach by the EU. The chapter also considers inter-organizational relations in sanctions behavior across levels of governance – national, regional, and global – and patterns of overlap, nesting, and cooperation between international entities. The dramatic rise of regional organizations as sanction senders has triggered interest in both legal studies and political science. Legal scholarship has documented the consolidation of mechanisms allowing regional arrangements to react to democratic backsliding. The chapter concludes with suggestions for future research.