Parent-report of child homework problems was examined as a treatment outcome variable in the MTA-Multimodal Treatment Study of Children with Attention-Deficit/Hyperactivity Disorder (ADHD). Five hundred seventy-nine children ages 7.0 to 9.9 were randomly assigned to either medication management, behavioral treatment, combination treatment, or routine community care. Results showed that only participants who received behavioral treatment (behavioral and combined treatment) demonstrated sustained improvements in homework problems in comparison to routine community care. The magnitude of the sustained effect at the 10-month follow-up assessment was small to moderate for combined and behavioral treatment over routine community care (d = 0.37, 0.40, respectively). Parent ratings of initial ADHD symptom severity was the only variable found to moderate these effects. (Contains 3 tables and 3 figures.)