Despite a rapid growth in research interest and treatment facilities for adolescent sex offenders, understanding of how these adolescents differ from non-offending adolescents remains incomplete. This study contributes to knowledge of the distinguishing characteristics of offenders and focuses on levels of sexual knowledge and empathy that differentiates adolescent sex offenders and normative comparators. Data were collected from 55 male non-offending adolescents and compared to 221 male adolescent child molesters of a similar age who had attended a treatment clinic. Measures used were the Sexual Matters Questionnaire (ADOL) and the Victim Empathy Scale. The present study found that adolescent sexual offenders have less sexual knowledge and less victim empathy skills than non-offending adolescents. Results are discussed in terms of ethical, methodological and intervention implications. (Contains 4 tables.)