The aim of the current study is to gain a better insight into the relationship between sexually aggressive behaviour and psychopathy in youths; juveniles who sexually offended (JSOs) were compared with generally offending youths and a general population group. Seventy-one JSOs, 416 detained general offenders, and 331 males from the general population were assessed by means of the Youth Psychopathic traits Inventory (YPI), a self-report instrument. Sexually and generally offending juveniles had significantly lower levels of self-reported psychopathic traits than youths from the general population. Juvenile sexual offenders and generally offending juveniles did not differ in self-reported psychopathic traits. Furthermore, no differences in self-reported psychopathic traits were found between subgroups of JSOs (i.e., child molesters, solo offenders, and group offenders). The finding that self-reported psychopathic traits are less prevalent in offending juveniles than in general population youths raises questions about the usefulness of the YPI when comparing psychopathic traits between clinical samples and general-population samples.