The First World War was a transformative event, affecting international culture, economics, and geopolitics. Though often presented as the moment heralding a new secular era of modernity, in actuality the war experience was grounded in religious faith and ritual for many participants. This Element examines how religion was employed by the state to solicit support and civic participation, while also being subordinated to the strategic and operational demands of the combatant armies. Even as religion was employed to express dissent, it was also used as a coercive tool to ensure compliance with the wartime demands of the state on civilians.