In recent years, inter-institutional cooperation has become an important topic in politics and academia alike. Increasing numbers of international, trans-national, and supranational organizations as well as the expansion of their respective role domains enhance both, the chance for interaction and cooperation and the possibility for rivalry and conflict. This paper proposes a theory of interinstitutional cooperation that explains the likelihood of inter-institutional relations which are determined by organizational autonomy and overlapping role domains. Whether these relations turn out to be cooperative or conflictive depends on joint interests, reciprocal dependency, power relations and institutional needs for legitimacy. The theory’s propositions are tested with the help of case studies from Europe, Africa and Asia.
