The Brown ADD Scale for Adolescents is used widely clinically yet no published studies have investigated divergent and concurrent validity, specificity and sensitivity to inattentive ADHD symptomatology. Ninety-eight participants (13 to 16 years) were classified as ADHD/I and/or reading disabled (RD) using K-SADS, Conners Rating Scales (CRS-R) and Ontario Child Health Study Scales (OCHSS), WRAT3 and WRMT-R, resulting in 29 ADHD/I; 12 RD, 16 ADHD/I with RD; and 41 controls. The RD group was included to evaluate specificity. The Brown was administered but not used in classification. The ADHD groups scored higher on the Brown subscales compared with the other two groups. The recommended cutoffs resulted in high rates of false negatives but few false positives; suggesting good specificity but poor sensitivity. There were moderate correlations among the Brown, CRS-R and OCHSS. The Brown can be useful in screening out ADHD; however, its low sensitivity precludes its usefulness in diagnosing ADHD.