This introductory essay synthesises the contributions to this special 5 issue on polar regions and multi-level governance, showing how they address three important themes in the study of institutional complexes: interplay management; the influence that global institutions and processes exert on regional regimes; and the ways in which states and other actors pursue their interests within com- 10 plexes of institutions. The institutional complexes in focus here comprise institutions relevant to Arctic Ocean governance, EU– Arctic relationships, Arctic maritime boundary disputes, the Antarctic Treaty System (including CCAMLR), the preservation of cultural heritage and the traditional economy in Newfoundland and 15 Labrador, and scientific research in Svalbard.