Perceptions of crime seriousness have been studied since the 1960s. Based predominantly on data from surveys, researchers have identified characteristics of acts affecting seriousness perceptions and have examined the degree of consensus in perceived seriousness for a variety of deviant and criminal behaviors. Methodological issues (methods of measurement, questionnaire structure and content, level or measurement, etc.) have been discussed at length. This review presents the most important substantive and methodological accomplishments and challenges of this body of research. It also discusses possible future directions, including the establishment of connections to sociological theory and normative philosophy.