Objective: This study compared practitioner self-report of ADHD quality of care measures with actual performance, as documented by chart review. Method: In total, 188 practitioners from 50 pediatric practices completed questionnaires in which they self-reported estimates of ADHD quality of care indicators. A total of 1,599 charts were reviewed. Results: The percentage of patients for whom practitioners self-reported that they used evidence-based care was higher in every performance category when compared with chart review, including higher use of parent and teacher rating scales during assessment and treatment compared with chart review. Self-reported use of Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) criteria during assessment was also higher than by chart review. The actual number of days until the first contact after starting medication was nearly three times longer than self-report estimates. Conclusion: Practitioners overreport performance on quality of care indicators. These differences were large and consistent across ADHD diagnostic and treatment monitoring practices. Practitioner self-report of ADHD guideline adherence should not be considered a valid measure of performance.