While research on regionalism is no longer in its infancy, most of the literature assumes that economic factors are the main drivers behind regional ties. This perspective misses the fact, that Regional Organizations (ROs) are also strongly driven by security concerns. Regional arrangements do not only contribute to security within the territory of the RO but also extent stability to their neighbourhoods. The most prominent example is the European Union (EU), which has strengthened its profile in foreign and security policy significantly during the last decades. One important feature of Europe´s international relations is the spread of interregional relations between the EU and counterparts, which increasingly focus on security issues. Therefore this paper sheds light on interregional security relations. Drawing on literature of regionalism, interregionalism as well as security studies, I develop a framework for the study of interregional security cooperation. After assessing security fields addressed by bi-regional partnerships in general, I specifically examine on interactions between the EU and the African Union (AU). EU-AU cooperation will be analysed more closely, since the two have high ambitions in tackling challenges for peace and security. One important question that will be asked in this respect concerns the effectiveness of the cooperation. Both multilevel cooperation efforts and the recently developing capacity of the African Peace Facility pose significant challenges for the partnership. My findings suggest that specific rationales such as differences in the member states approach to conflict resolution, domestic scepticism regarding external engagement as well as the rationale of enhancing partners further on are drivers for the growing importance of interregional ties. EU-AU relations address a wide range of security issues and can to some extent be perceived as effective means of Europe´s foreign policy. The paper thus indicates the relevance of interregional security cooperation in EU´s external relations.
