Non-refoulement is a principle of international law that precludes states from returning a person to a place where he or she might be tortured or face persecution. The principle, codified in Article 33 of the 1951 Refugee Convention, is subject to a number of exceptions. This article examines the status of non-refoulement in international law in respect to three key areas: refugee law, human rights law and international customary law. The findings suggest that while a prohibition on refoulement is part of international human rights law and international customary law, the evidence that non-refoulement has acquired the status of a jus cogens norm is less than convincing.