In Serbia, during the 2015 European refugee crisis, the Orthodox Church mobilized communities in providing humanitarian aid before local authorities and the government issued an organized response. Two years later, in December 2017, with the support of the Orthodox Church, Ukraine exchanged war prisoners with the separatist authorities in Donbas. In both countries, the social and political involvement of Orthodox Churches in dealing with forced displacement was unprecedented. Drawing on literature review and interviews with 25 representatives of governmental and civil-society bodies, members of the clergy and academics, this article explores the ways in which, in Serbia and Ukraine, when states fail to offer support for populations affected by violence, religious communities have been among the first actors to take over state governance and provide human security. It argues that, by doing so, Orthodox Churches become open to politicization from state authorities. The article contributes to the study of religion and forced displacement by linking the politicization of Orthodox Churches to the concept of state failure.