The present study was designed to investigate the discriminant validity of the Devereux Scales of Mental Disorders (DSMD; Naglieri, LeBuffe, & Pfeiffer, 1994) in relation to a widely used behavior rating scale, the Teacher Report Form (TRF; Achenbach, 1991), in children and adolescents with emotional disturbance (ED). A matched sample of 148 children and adolescents, 74 in regular education and 74 in special education settings for ED, were rated by teachers using the DSMD and TRF. Multivariate analysis of variance (MANOVA) analyses and d-ratios yielded statistically significant differences (p less than 0.01) between groups and moderate to large effect sizes. Receiver operator characteristic analyses indicated that in general the TRF produced higher area under the curve (AUC) estimates than the DSMD across age groups for the total and composite scale scores. Classification efficiency statistics at the recommended cutoff T-score of 60 for the total scale revealed that the DSMD performed as well as the TRF. Results generalized well across base rates, with the DSMD producing slightly higher positive predictive power than the TRF, and the TRF exhibiting a greater negative predictive power than the DSMD. (Contains 4 tables, 4 figures and 1 note.)