Objective: Studies on comorbidity in children diagnosed with ADHD have relied more on parent/teacher reports instead of self-reported data and have focused on the frequency of comorbid symptoms instead of scores above clinical cutoffs. The purpose of this study was to examine the prevalence of oppositional defiant disorder (ODD), anxiety, and depression in children with ADHD, using self-report measures for internalizing symptoms and parent-reported measures for externalizing symptoms for increased accuracy. Gender differences were also assessed. Method: Parents of 197 children diagnosed with ADHD answered the Disruptive Behavior Rating Scale, and 112 of the children filled out the Multidimensional Anxiety Scale for Children and the Children’s Depression Inventory. Results: Results revealed that 19.28% of the children met cut-off criteria for ODD, 41.96% for anxiety, and 21.43% for depression. Conclusion: Our findings indicate a relatively lower prevalence of ODD and a slightly higher prevalence of anxiety symptoms than previously reported. Possible explanations and future directions are discussed.