A constructive debate over the classification of child psychopathology can be stimulated by investigating the validity of different classification approaches. We examined and compared the short-term predictive validity of cluster analytic and dimensional classifications of child behavioral adjustment in school using the Behavior Assessment System for Children (BASC; [Reynolds, C. R., and Kamphaus, R. W. (1992). "Behavior Assessment System for Children (BASC)." Circle Pines, MN: AGS.]) Teacher Rating Scales for Children (TRS-C). We cluster analyzed 14 dimensional scores of children's behavior in first grade and identified seven clusters. Then we examined the predictive power of the dimensions and the clusters using a variety of school outcomes in second grade, including academic achievement scores in reading and math, absenteeism, discipline reports, and participation rates in pre-referral intervention. Both methods significantly predicted all school outcomes with similar magnitudes of effect sizes, but the dimensional approach was more powerful in predicting the outcomes except pre-referral intervention. Moreover, coherent group differences in the clusters were identified with respect to the school outcomes. This latter finding may suggest differentiated prognoses of cluster membership. The implications for future validation studies of alternative classification systems of child behavioral adjustment are discussed.