In any society influenced by a plurality of cultures, there will be widespread, systematic differences about at least some important values, including moral values. Many of these differences look like deep disagreements, difficult to resolve objectively if that is possible at all. One common response to the suspicion that these disagreements are unsettleable has always been moral relativism. In the flurry of sympathetic treatments of this doctrine in the last two decades, attention has understandably focused on the simpler case in which one fairly self-contained and culturally homogeneous society confronts, at least in thought, the values of another; but most have taken relativism to have implications within a single pluralistic society as well. I am not among the sympathizers. That is partly because I am more optimistic than many about how many moral disagreements can be settled, but I shall say little about that here. For, even on the assumption that many disputes are unsettleable, I continue to find relativism a theoretically puzzling reaction to the problem of moral disagreement, and a troubling one in practice, especially when the practice involves regular interaction among those who disagree. This essay attempts to explain why.