Co-occurring internalizing symptoms are common and important to assess in children with attention-deficit/hyperactivity disorder (ADHD). One frequently used child self-report measure of internalizing symptoms is the Revised Child Anxiety and Depression Scales (RCADS), yet the psychometric properties of the RCADS remain unexamined in children referred for ADHD specifically. The present study evaluated the RCADS in 117 children (ages 8–12; 66% male) evaluated for suspected ADHD at an ADHD specialty clinic (83% met criteria for ADHD). In addition to the RCADS, children completed measures of social anxiety and depression. Parents completed the RCADS-Parent Version (RCADS-P) in addition to other measures of internalizing and externalizing symptoms. Children and parents both completed a measure of aggression. Factor structure, reliability, and convergent/discriminant validity of the RCADS were examined. Results supported the six-factor structure of the child-report RCADS (Separation Anxiety, Social Phobia, Generalized Anxiety Disorder, Panic Disorder, Obsessive Compulsive Disorder, and Major Depressive Disorder). The RCADS demonstrated adequate reliability as well as convergent and discriminant validity with other child ratings. The total anxiety score on the RCADS also demonstrated convergent and discriminant validity with parent measures, though the depression score on the RCADS did not. Findings provide preliminary psychometric support for the RCADS in children referred for ADHD.