How do religion and ethnicity shape the sustainability of peace after civil wars? Ethnic and religious conflicts have been rising in prevalence over the last half-century, generating larger headlines as they influence every corner of the world. These conflicts occur across faiths, sects, and nations, and they appear to reignite in intervals, devolving into conflict again and again with spells of relative peace in between. With some notable exceptions, previous research on conflict recurrence has focused primarily on either ethnicity or religion, resulting in limited understanding of the ways that religion and ethnicity may interact. Moreover, many studies simplify the study of religion, ethnicity, and conflict by reducing it to an issue of shared identity, i.e., whether the two warring parties are from the same nominal religious or ethnic group. This project explores the role that religion and ethnicity play in three major causes of conflict recurrence: post-war autonomy, peacetime discrimination, and territorial claims. The primary argument is that religious and ethnic identities drive conflict recurrence through territorial claims, achieving autonomy, and their reactions to discrimination. Using a stratified Cox Proportional Hazard model, I analyze global data on all post-intrastate armed conflict peace years between 1980 and 2006. The results suggest that the indivisibility of territory in religious conflicts makes conflict more likely to recur, but only in cases where the fundamental question at hand is the role of religion in government. In addition, conflicts organized around ethnicity are increasingly unlikely to respond to discrimination by returning to war. The extreme scarcity of post-war autonomy arrangements rendered robust conclusions about its effect difficult to discern.