Rules are a ubiquitous normative form across the human experience. The recent anthropology of ethics and morality has, however, tended to focus elsewhere, in part to redress a perceived earlier over-emphasis on rules within anthropology. Bourdieu’s scepticism as to the value of structuralist talk of rules, and favouring instead of ‘practice’, has been more widely influential. This chapter makes the case for a renewed and more sophisticated attention to rules within the anthropology of ethics. While the roots of anthropological rule scepticism lie in debates – often inspired by Wittgenstein – over whether the implicit norms of ‘ordinary’ social life should be thought of as ‘rules’, the prominence of explicit rules in many of the world’s great ethical traditions seems hard to ignore. And yet, the conceptual tools available to anthropologists for their nuanced ethnographic appreciation remain under-developed. Some potential resources from analytic and legal philosophy and moral theology are brought to bear on examples from the author’s research on the use of religious rules, specifically those of the Islamic sharia. Having demonstrated the diversity, complexity, and ethnographic interest of the practice of moral rules, the chapter ends by considering why some social contexts appear more ‘ruly’, or legalistic, than others.