BACKGROUND: DSM-5 provided a dimensional model of personality disorders which may be more clinically informative for the assessment and management of prisoners than a categorical one, as diagnoses of personality disorders alone cannot explain the type of violence. The role of DSM-5 personality facets is however understudied in child molesters, and no study compared these clinical features between individuals who have committed sex crime against children and those who have committed other types of crime. The present study compared DSM-5 personality trait facets between prisoners who had committed sex crime against children, prisoners who had committed property crime (i.e., robbery, fraud) and those who had committed crime against the person (i.e., homicide, assault or violence not implying a sexual element). A further aim was to explore which facets were associated with sex crime against children as compared with the other types of crime, controlling for socio-demographics (age, gender), psychiatric comorbidity (presence of any psychiatric diagnoses) and general psychopathy traits. METHODS: One hundred sixty-seven prisoners participated (91 had committed sex crime against children, 25 property crime, and 51 committed a crime against the person) and completed the Personality Inventory for the DSM-5 and the Psychopathy Checklist-Revised. RESULTS: Prisoners who had committed sex crime against children reported higher Restricted Affectivity traits than those who had committed property crime and crime against the person and higher Irresponsibility traits than those who had committed property crime. The results of a multinomial logistic regression analysis showed that on the one hand being a man, having a higher age, and the presence of a psychiatric comorbidity were more likely to be related to sex crime than property crime, on the other hand higher Irresponsibility personality traits, being a man, and the presence of a psychiatric comorbidity were more likely to be related to sex crime against children than crime against the person. CONCLUSIONS: The Irresponsibility facet might be specific to child molesters and can differentiate this group from offenders who have committed other crime types. This facet might be considered a key target of a tailored assessment and treatment planning during clinical practice with child molesters.