The purpose of this study was to assess the concurrent criterion validity of the attention-deficit/hyperactivity disorder (ADHD) portion of the National Institute of Mental Health Diagnostic Interview Schedule for Children-IV (NIMHDISC-IV). Fifty-seven adolescent participants were divided into three groups on the basis of whether participants met criteria for ADHD on caretaker and adolescent responses on the DISC: (a) 18 participants for whom both the caretakers and adolescents endorsed ADHD, (b) 17 participants for whom the caretakers but not the youth endorsed ADHD, and (c) a clinical control group with no ADHD diagnosis (n = 22). These three groups were compared across parent, teacher, and adolescent checklists; clinician diagnosis; and three objective measures of behavior (continuous performance task, actigraphy monitoring, and a structured observation). Findings lend partial support to the concurrent criterion validity of the ADHD section of DISC.