This study aims to determine the effects of the Parents Plus Children's Programme (PPCP) on children's symptoms of attention deficit and hyperactivity disorder (ADHD) and on family functionality and parenting stress. The children in the study were aged 6-11 years, and they had been diagnosed with ADHD and had residual symptoms despite effective dosage and timing of their medication. Forty-six couples, who with their children met the eligibility criteria, were enrolled and randomly allocated to the PPCP or the control group. The intervention involved a 9-week, 2 h a week, parenting group exercise. Those in the PPCP group improved significantly more over time on Conners' Parent Rating Scale-Revised, Family Assessment Device, and Parent Stress Index than those in the control condition. The trial is the first clinical study involving the parents of children with ADHD that addresses residual symptoms and functional impairments that remain despite the administration of the maximum effective dose of pharmacological treatment.