Youths were referred by the court to an intervention program; ratings of delinquency and aggression were derived from parent reports, self-reports, and court referral data. Results showed that high parent ratings of youth aggressiveness were related to high turmoil in the home and to youths' positive opinions of delinquent peers, while high aggressiveness of the youths' referring offenses was related to lax punishment. Developmentally, this suggests that in adolescence both the peer group and home influences are important in shaping different aspects of the youths' aggressive and delinquent behaviors. (Author abstract)