The purpose of this study was to analyze the effects of an intensive psychosocial intervention on the executive functioning (EF) in children with ADHD. The treatment was carried out in a coordinated manner over a period of 10 weeks with 27 children with ADHD aged 7 to 10, their parents, and their teachers. A battery of neuropsychological tasks was applied to evaluate attention, interference control, verbal and visuospatial working memory, planning ability, and flexibility. The comparative analysis of the treated group of ADHD children and an untreated ADHD group showed significant differences that were especially important in visuospatial memory and planning in favor of the treated children, even when the scores in the pretreatment phase were included as covariables. Likewise, improvements were observed in the parents’ and teachers’ behavioral ratings of hyperactivity or impulsivity and inattention. The conclusion was drawn that psychosocial interventions with children with ADHD can have a positive effect on some executive functions.