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 for the assessment of Oppositional Defiant Disorder (ODD) in youth. Although there is considerable evidence that the ADIS–P is effective in diagnosing anxiety disorders in youth, no studies have yet examined its validity in assessing ODD. In contrast, a number of studies support the Diagnostic Interview Schedule for Children–Version IV (DISC–IV) as a reliable and valid tool in the assessment of ODD. In the present study, the ADIS–P and DISC–IV ODD modules were administered in a counterbalanced order to the parents of a clinical sample of 106 children between 7 and 14 years of age referred for the treatment of ODD. It was hypothesized that the ODD module of the ADIS–P would be valid as determined by its concurrent and convergent validity with the DISC–IV, the Behavior Assessment System for Children (BASC) Aggression and Conduct Problems scales, and the Disruptive Behavior Disorders rating scale (DBD). Results demonstrated that ADIS–P ODD diagnoses had moderate agreement with DISC–IV ODD diagnoses (κ = .46, p < .001) and that Pearson correlations of ADIS symptom counts with questionnaire scales were similar in magnitude with correlations of DISC–IV symptom counts with the same questionnaires. Overall, findings suggest that clinicians and researchers can use the ADIS–P as an empirically-supported diagnostic interview for assessing children’s oppositional problems.