Plato’s Laws include what H.L.A. Hart called the ‘classical thesis’ about the nature and role of law: the law exists to see that one leads a morally good life. This paper develops Hart’s brief remarks by providing a panorama of the classical thesis in Laws. This is done by considering two themes: (1) the extent to which Laws is paternalistic, and (2) the extent to which Laws is naturalistic. These themes are significant for a number of reasons, including because they show how Laws might be viewed as a sophisticated forerunner of natural law theory. The upshot is that Plato’s metaphysical commitments about legal ontology allow him to base the truth of legal propositions on the way they relate to the truth of corresponding moral propositions.