Objective: Children with ADHD frequently manifest behavioral difficulties in the morning prior to school. We sought to assess the reliability and validity of the Daily Parent Rating of Evening and Morning Behavior Scale, Revised (DPREMB-R) morning score as a measure of morning behaviors impaired by ADHD. Method: We used data from a clinical trial of HLD200 treatment in pediatric participants with ADHD to address our objectives. Results: The DPREMB-R morning score showed significant internal homogeneity, test–retest reliability (r = .52-.45), and good concurrent validity (r = .50-.71). Conclusion: The DPREMB-R morning score could be a useful instrument for assessing treatment efficacy in the morning before school.