This research study funded by the Department of Justice, Office of Juvenile Justice and Delinquency Prevention was premised on the contention that juvenile sex offenders represent a heterogeneous population, with various intervention needs, and that an objective means in identifying distinct subgroups of these youths would enhance criminal justice and mental health management efforts. It was believed that a classification methodology would assist the criminal justice system in determining which juveniles could be safely managed in the community and which ones required institutional or correctional placement leading to the refinement of treatment programs and early identification and intervention efforts. A combination of archival and prospective data was successfully collected on 182 adolescent males with institutionally documented histories of sexual offending. A structural equation model was used to assess theorized relationships between development risk factors, personality mediators, and sexual offense characteristics in predicting whether sexual offenses were committed against pubescent females or prepubescent children. Follow-up univariate regression analyses were conducted. Offenders of children showed greater deficits in psychosocial functioning than offenders of pubescent females, were less aggressive in their sexual offending, and were more likely to offend against victims to whom they were related. Psychosocial deficits played an important mediating role in explaining the effect of exposure to violence against females on both sexual aggression and non-sexual violence and delinquency. Physical abuse by a father or stepfather, and exposure to violence against females, contributed to the prediction of co-morbid anxiety and depression, while non-coercive childhood sexual victimization by a male non-relative predicted adolescent sexual perpetration against a male child. The results of the pilot study supported the viability of creating a typology of the juvenile sexual offender based on causal modeling of the influences of developmental experiences, personality traits, and offender characteristics. The results suggested that further explication of the relationship between personality traits and offender characteristics, and delineation of offender subtypes, could be achieved through additional research.