Rules play a central role in Sellars’s philosophy. As Sellars writes in “Language, Rules, and Behavior,” “When God created Adam, he whispered in his ear, ‘In all contexts of action you will recognize rules, if only the rule to grope for rules to recognize.’ When you cease to recognize rules, you will walk on four feet” (p. 298). However, radical particularists in ethics argue (often on the basis of holism about reasons) that rules play no role in ethical judgment or moral justification. I argue in this chapter that while radical particularism is not very plausible, it is incumbent upon the Sellarsian to develop a notion of a rule that has genuine force but admits of exceptions—that can serve the role of Sellars’s important material inferential rules. Fortunately, recent years have seen the emergence of well-developed accounts of defeasible rules of inference—both less formal accounts (like Mark Lance and Margaret Little’s) and formal ones (like John Horty’s). I show how these accounts can be pressed into service for Sellars’s philosophical project.