Although populism has been a prominent topic in the social sciences, until very recently little attention has been paid to its inter-and transnational dimensions. While populism researchers have mainly focused on theoretical and methodological issues, or studied individual cases (whether in single case studies or in a comparative fashion), International Relations scholars have until recently largely ignored the phenomenon. At the latest with the return of Donald J. Trump to the US presidency, the need for research on the nexus between populism and world politics has become a pressing issue. This introduction (1) provides a critical overview of the burgeoning IR literature on populism, (2) makes the case for a more systematic engagement between the IR and populism research outside the discipline, (3) provides an overview of the chapters of the volume and situates their individual contributions within the larger framework of the populism-world politics nexus