This paper discusses the implications of the ethical theory of Emmanuel Levinas for theoretical debates about legal obligation. I begin by examining the structure of moral reasoning in light of Levinas's account of ethics, looking particularly at the role of the third party (le tiers) in modifying Levinas's primary ethical structure of the face to face relation. I then argue that the primordial role of ethical experience in social discourse, as emphasised by Levinas, undermines theories, such as that of H. (...) L. A. Hart, that propose a systematic distinction between legal and moral species of obligation. (shrink)