BackgroundSiblings of children with disabilities also need support. However, there are only a few evidence-based interventions for these siblings. The current study aims to assess the effectiveness of a newly developed serious game for young siblings of children with intellectual disability (ID) and/or visual impairment (VI). This serious game is hypothesized to improve sibling’s quality of life, adjustment to their brother’s or sister’s disability, and multiple aspects of psychosocial well-being.MethodsThe intervention consists of a serious game called “Broodles” (in Dutch: “Broedels”) that helps children to recognize and deal with thoughts, feelings, and difficult situations. The game consists of eight 20-minute levels that all have the same structure with eight game elements. Each level addresses a domain of sibling quality of life and combines animations, mini-documentaries, fun mini-games, and multiple-choice questions. In addition to the game, siblings make a worksheet after playing each level. In order to support the child, the parents or caregivers receive a short brochure with information and tips. The effectiveness of the intervention will be investigated among a sample of 154 children aged 6–9 years and their parents or caregivers, using a two-arm parallel RCT design. The experimental group will play the serious game “Broodles” over a period of 4 weeks, whereas the control group will be placed on a waiting list. Assessments will take place at three time points: pre-test (week 1), post-test (week 5), and follow-up (weeks 12–14). At each timepoint, children and parents will complete several questionnaires on quality of life and different aspects of psychosocial well-being. In addition, children will make drawings to assess the sibling relationship. Next to that, parents and children will answer closed and open-ended questions about the sibling adjustment to their brother or sister’s disability. Finally, parents and children will evaluate the serious game through closed and open-ended questions.DiscussionThis study contributes to the knowledge about sibling interventions and serious games. Additionally, if the serious game is proven to be effective, it will be a readily available, easily accessible, and free of charge intervention for siblings.Trial registrationClinicalTrials.gov, NCT05376007, registered prospectively on April 21, 2022.