Why are some factions fighting for greater national self-determination (SD) more violent than others? While previous explanations of violence in these disputes have focused on the number of factions, their internal structures, and power distributions among factions, we find many factions that do not follow the expectations of these theories. In this article, we center on religious ideology, its unique transnational character, and the opportunity it creates for political elites from competing factions within the same SD movement to mobilize support. We argue that “religious factions” have a greater incentive to use violence than other factions. Violence serves as a costly signal, and it can be used to demonstrate a faction’s religious credentials to transnational networks and contacts, as they compete with each other on the international stage for the same potential benefactors. We code original data on the religious ideology of factions. We find that an increasing number of religious factions is associated with increased religious faction use of violence. Furthermore, our findings point to a critical insight: it is not religious ideology, but competition between religious factions, that generates violence.