Virtually all corners of the world have, at one point in history, experienced episodes of ethnoreligious conflicts. For many sovereign states today, however, intense clashes between competing ethnoreligious groups continue. This paper examines how ethnoreligious conflicts rise and remain entrenched over long periods of time. Although the current literature provides significant insights about the multiple factors that give rise to these conflicts and to what extent, what is mostly missing are explanations about the dynamics and processes in which these causes are crystallized and animated. Hence, in this paper, I develop and test a framework that identifies and explains the three key stages through which overlapping rationalist, non-rationalist, and instrumentalist causes develop into lasting ethnoreligious conflicts: cultivating ethnoreligious nationalism; securitizing the ethnoreligious others; and sacralizing territorial-cultural identities. The framework enables a more holistic appreciation of the contexts, actors, and motives underpinning these events in multiethnic and multireligious territorial communities.