It is often maintained that the criminal law is supposed to intervene only when a certain social norm has become so significant within a given society to justify its protection by means of penal sanctions. The criminal law is thus thought to mirror a hierarchy of values it neither shapes nor contributes to building; rather, it is required to stand at least one step behind social change. This article challenges this view, presenting a normative account that contributes to the debate on what is permissible for the criminal law to try to achieve. It does so by defining and theoretically substantiating the “transformational function” of the criminal law. The term refers to the use of criminalization and punishment to change, rather than merely reflect, social norms, attitudes, and beliefs alongside, and combined with, non-penal policy-making tools in contested domains. Four operational conditions of legitimacy are identified and discussed. Within such operational boundaries, this article contends that the criminal law can play an important role in promoting social change—i.e., the establishment of new norms and values—as well as helping the coagulation of norms, attitudes, and beliefs not yet fully entrenched within the societal body.