This workshop explored the evolution of legitimacy deficits and tensions and their impact on cooperation, using empirical examples, in particular from the Arctic regions, where cross-border cooperation between state- and non-state actors has a long tradition. To understand the roots of contested formats of cooperation in the Arctic regions without limiting the scope of research to a “before and after February 2022”, the workshop participants discussed examples from the North American, European and Russian Arctic regions to better explain the evolution of legitimacy deficits and tensions, and assessed them in the light of different theoretical perspectives on legitimacy and legitimation. Thereby, the participants in this workshop moved beyond the classification of an “Arctic exceptionalism” and explored how observations from the Arctic also correspond to findings from legitimacy-studies in other regions and fields of research.