Asylum lies at the heart of the international refugee protection regime. Yet, today, most states in the developed world implement a range of deterrence measures designed to prevent access to asylum on their territories. With particular attention to Europe’s response to the Syrian refugee crisis, this paper categorizes contemporary deterrence policies. It then questions the sustainability and effectiveness of such policies. A number of deterrence measures do not conform with refugee and human rights law, rendering the refugee protection regime vulnerable to collapse. Finally, this article suggests some ways forward to address these problems. It discusses the partial success of legal challenges to deterrence measures and opportunities for alternative avenues to access protection. Ultimately, however, it argues that the viability of the refugee protection regime requires collective action and international burden-sharing.