The normative approach to Milgram’s experiment argues that participants do not obey because of submission to authority, but because they are following explicit and previously justified rules. However, this approach remains theoretically ambiguous and empirically imprecise, due to a confused use of the concept of normative necessity. In this article, I draw on Anscombe’s account of practice to clarify this concept and to develop a more precise interpretation of the subjects’ behavior within Milgram’s experimental framework.