The research regarding assessments of juvenile sex offenders indicates that risk assessment holds the most promise in reliably estimating the risk of reoffense. In terms of treatment outcomes, research suggests that cognitive behavioral treatments and multisystemic therapy are most effective at reducing sexual reoffending among juvenile populations. Accurately assessing and treating juvenile sex offenders is crucial for the development of the juvenile as well as for the safety of the community. The authors begin their examination of the effectiveness of assessments and treatments for juvenile sex offenders with a review of the reliability and validity of self-report instruments, objective assessment instruments, and risk assessment instruments. Self-report instruments are limited by the potential for response bias and by a lack of evidence concerning their validity and reliability. Objective assessment instruments also lack conclusive evidence of their validity and some methods, such as plethysmograph, bring up ethical issues related to their use with juvenile populations. Research evidence of the effectiveness of treatment with juvenile sex offenders is examined and focuses on cognitive behavioral treatments, psychosocial educational treatments, multisystemic therapy, and non-sex-offender specific treatment. Despite methodological limitations in treatment evaluation research, findings do suggest that treatment can be effective in reducing sexual offending among juvenile sex offenders, particularly cognitive behavior and multisystemic therapies. Future research should probe the utility of specialized treatment with juvenile sex offender populations because evidence to date suggests specialized treatment may be of limited utility. Tables, references