Greece and Turkey have found themselves on the brink of war on several occasions over the last 50 years irrespective of the fact that both have been members to NATO since 1952. This book sets out to explore the effects this co-membership of Greece and Turkey in NATO has had on the course of their bilateral conflict while paying attention to the related theoretical debate and portraying the arguments of neorealists and neoliberal institutionalists. A further object of research is the impact of NATO membership on the democratic development of these countries. Overall, the conclusion is drawn that NATO has not played a prominent role in this conflict, and the effects of membership have been ambivalent. Moreover, NATO membership neither seems to have played a major role in shaping the fate of democratization in these countries. Nevertheless, the assertion is made that these findings do not contradict institutionalist argumentation, since the effects of institutions are expected to vary in different settings.