Families of children with Attention Deficit Hyperactivity Disorder (ADHD) often report morning and bedtime routines to be stressful and frustrating. Through a design process involving domain professionals and families we designed MOBERO, a smartphone-based system that assists families in establishing healthy morning and bedtime routines with the aim to assist the child in becoming independent and lowering the parents’ frustration levels. In a two-week intervention with 13 children with ADHD and their families, MOBERO significantly improved children’s independence and reduced parents’ frustration levels. Additionally, use of MOBERO was associated with a 16.5% reduction in core ADHD symptoms and an 8.3% improvement in the child’s sleep habits, both measured by standardized questionnaires. Our study highlights the potential of assistive technologies to change the everyday practices of families of children with ADHD.