The executive function (EF) deficits of children with attention deficit hyperactivity disorder (ADHD) hinder their performance of complex daily functions. Despite the existing evidence-based pharmacological interventions for ADHD symptoms, no intervention has yet been found that deals directly with EFs in daily tasks. Fourteen children and their parents participated in the Cognitive–Functional (Cog–Fun) program in occupational therapy, which is tailored to the executive dysfunction of ADHD and focuses on enabling cognitive strategies for occupational performance. The study included initial assessment of EFs (Behavior Rating Inventory of Executive Functions; Tower of LondonDX), occupational performance (Canadian Occupational Performance Measure), 10 sessions of Cog–Fun intervention with each child–parent dyad, and postintervention and 3-month follow-up assessments. We found significant improvements with medium to large effects on outcome measures after intervention, and most effects were maintained at follow-up. The findings warrant controlled studies examining the effectiveness of this intervention for children with ADHD.