Many in the media have depicted conflicts between the Western and Muslim worlds as a ‘Clash of Civilizations’ (CoC), and this has revived many of the questions surrounding the value of Samuel Huntington’s CoC theory. Previous empirical tests have analysed his theory using low-level conflict at the interstate level or violent conflict at the subnational level. The former have demonstrated little or no empirical support for his theory, while the results in the latter group are mixed. This analysis adds to previous empirical studies in a number of ways. One, the empirical models test CoC exclusively in the post-Cold War era. Two, along with examining the civilizational determinants of military interstate disputes, as prior studies have done, I include models that focus exclusively on interstate wars, because Huntington frequently points out that a CoC between states will lead to violent political conflict. Finally, this study directly tests Huntington’s civilizational ‘fault lines’ and Islamic ‘bloody border’ hypotheses. I include an extension and find that intra-civilizational conflict is relatively rare in the post-Cold War era. Contrary to earlier analyses, the data show strong empirical support for CoC, particularly when focusing on violent international conflict in the post-Cold War era, and the results are robust when testing the hypotheses with alternative data on international crises.