This chapter is inspired by Ian Loader and Richard Sparks’ call to exercise ‘public criminology,’ that is, their plea to all criminologists to contribute rigorous knowledge and innovative and provocative theoretical reflections to public and policy debates on crime and criminal policy. It considers whether public perceptions of crime seriousness are a valid indicator of the actual seriousness of crime, an important criterion for many criminal policy decisions. Drawing on the cultivation theory of Gerbner and colleagues, numerous studies argue that media consumption influences public attitudes towards crime. The chapter explores the logic or normative philosophical principles with which the public assesses crime seriousness and consider the extent to which that logic aligns with legal principles. It examines the relative weights of perceived wrongfulness and perceived harmfulness and thus ‘moralist’ and ‘consequentialist’ concerns in public crime seriousness perceptions. Given the possibility of biases in people’s assessments of the seriousness of crime, policy-makers would be reckless to let criminal policy decisions.