This article describes the development and initial validation of the Juvenile Sexual Offense Recidivism Risk Assessment Tool–II (JSORRAT-II). Potential predictor variables were extracted from case file information for an exhaustive sample of 636 juveniles in Utah who sexually offended between 1990 and 1992. Simultaneous and hierarchical logistic regression analyses were used to identify the group of variables that was most predictive of subsequent juvenile sexual recidivism. A simple categorical scoring system was applied to these variables without meaningful loss of accuracy in the development sample for any sexual (area under the curve [AUC] = .89) and sexually violent (AUC = .89) juvenile recidivism. The JSORRAT-II was cross-validated on an exhaustive sample of 566 juveniles who had sexually offended in Utah in 1996 and 1997. Reliability of scoring the tool across five coders was quite high (intraclass correlation coefficient [ICC] = .96). Relative to the development sample, however, there was considerable shrinkage in the indices of predictive accuracy for any sexual (AUC = .65) and sexually violent (AUC = .65) juvenile recidivism. The reduced level of accuracy was not explained by severity of the index sexual offense, time at risk, or missing data. Capitalization on chance and other explanations for the possible reduction in predictive accuracy are explored, and potential uses and limitations of the tool are discussed.