Objective: This study aimed to determine whether the Strengths and Difficulties Questionnaire (SDQ) is an effective screening tool for identifying comorbid mental health difficulties in children with ADHD. Method: Parents of children with ADHD (5-13 years) completed the SDQ and the Anxiety Disorders Interview Schedule for DSM-IV–Parent Version (ADIS-C/P-IV). Data from both the measures were compared to determine congruent validity. Results: Analyses revealed that significant relationships exist between the SDQ total score and the total number of comorbidities on the ADIS-C/P-IV. The SDQ emotional problem and conduct problem scales were significantly related to internalizing and externalizing comorbidities on the ADIS-C/P-IV, respectively. Conclusion: While significant relationships were found between the SDQ and ADIS-C/P-IV across various domains, this relationship was stronger for externalizing comorbidities. Additional screening questions are required to effectively screen for less common internalizing comorbidities in children with ADHD, for example, major depression and panic disorder.