Objectives Learning and performing new routines are difficult for children with neurodevelopmental disorders. Studies have shown that consistency in child reinforcement and parental support are effective. For example, digital solutions such as serious games can be used to support parents and children in developing these life skills. The objective of this study was to evaluate the effect of a serious game on the performance of daily routines by autistic and ADHD children. Methods A total of 201 families (parents and children) participated in the study. The study used a combined 3 (intervention) × 3 (diagnosis) × 3 (time) research design with repeated measures. Participants were randomly assigned to three intervention groups (serious game, parental support, and a combination of serious game and parental support) based on their diagnosis (ASD, ADHD, neurotypical). Latent growth modeling and repeated ANOVAS were performed to analyze routine scores collected at three moments (baseline, midpoint, persistence) over an 8-week period. Results Results show a moderating effect of diagnosis on child routine trajectory. For ADHD participants, we observed a very important significant clinical effect for two interventions (parental support alone and combination of serious game and parental support) where for ASD children, this effect is observed for only one treatment (combination of serious game and parental support). For neurotypical children, results indicate a very important and significant clinical effect when they use the serious game alone. Conclusions Results show that the serious game can improve children’s routines. However, for some neurodevelopmental profiles (ASD or ADHD), the addition of parental support produces greater clinical improvements.