Risk assessment is considered to be a key element in the prevention of recidivism among juvenile sex offenders (JSOs), often by imposing long-term consequences based on that assessment. The authors reviewed the literature on the predictive accuracy of six well-known risk assessment instruments used to appraise risk among JSOs: the Juvenile Sex Offender Assessment Protocol-II (J-SOAP-II), Juvenile Sexual Offence Recidivism Risk Assessment Tool-II (J-SORRAT-II), Estimate of Risk of Adolescent Sexual Offence Recidivism (ERASOR), Juvenile Risk Assessment Scale (JRAS), Structured Assessment of Violent Risk in Youth (SAVRY), and Hare Psychopathy Checklist:Youth Version (PCL:YV). Through a systematic search, 19 studies were reviewed. Studies showed differences in the predictive accuracies for general, violent, and sexual recidivism, and none of the instruments showed unequivocal positive results in predicting future offending. Not unexpectedly, the accuracy of the SAVRY and PCL:YV appeared to be weaker for sexual recidivism compared with specialized tools such as the J-SOAP-II or the ERASOR. Because of the rapid development of juveniles, it is questionable to impose long-term restrictions based on a risk assessment only. New challenges in improving risk assessment are discussed.