Prevailing theory assumes that people enforce norms in order to pressure others to act in ways that they approve. Yet there are numerous examples of “unpopular norms” in which people compel each other to do things that they privately disapprove. While peer sanctioning suggests a ready explanation for why people conform to unpopular norms, it is harder to understand why they would enforce a norm they privately oppose. The authors argue that people enforce unpopular norms to show that they have complied out of genuine conviction and not because of social pressure. They use laboratory experiments to demonstrate this “false enforcement” in the context of a wine tasting and an academic text evaluation. Both studies find that participants who conformed to a norm due to social pressure then falsely enforced the norm by publicly criticizing a lone deviant. A third study shows that enforcement of a norm effectively signals the enforcer’s genuine support for the norm. These results demonstrate the potential for a vicious cycle in which perceived pressures to conform to and falsely enforce an unpopular norm reinforce one another.