The purpose of this study was to determine whether the Anxiety Disorders Interview Schedule for DSM–IV: Parent Version (ADIS–P) is a valid diagnostic tool in assessing Oppositional Defiant Disorder (ODD) in youth. Although there is considerable evidence that the ADIS–P is effective when diagnosing anxiety disorders in youth, no studies have yet examined its utility in assessing ODD, even though the ADIS–P contains an ODD module. In contrast, a number of studies support the Diagnostic Interview Schedule for Children–Version IV (DISC–IV) as a reliable and valid tool for assessing ODD. The two diagnostic interviews have not been compared to determine whether the ADIS–P might be equally valid to the DISC–IV in diagnosing ODD. In this study, the ADIS–P and DISC–IV ODD modules were administered in a counterbalanced order to the parents of a clinical sample of 53 children between 8 and 13 years of age referred for the treatment of ODD. It was hypothesized that the ODD module of the ADIS–P would be reliable, as evidenced by inter-rater correspondence, and valid as determined by its concurrent validity with the DISC–IV and its relations with the Behavior Assessment System for Children (BASC) Aggression and Conduct Problems scales as well as the Disruptive Behavior Disorders rating scale (DBD). Both of these latter instruments were completed by parents and teachers of the referred youth. Results suggest that the ADIS–P provides a valid assessment of ODD, giving clinicians and researchers another empirically-supported interview to use when assessing children's disruptive behaviors.