Gamified digital interventions are increasingly used to support children and adolescents with ADHD, yet it remains unclear which types of game designs are most therapeutically effective. This meta-analysis synthesized evidence from 24 randomized controlled trials including 1,948 participants to examine both overall intervention effects and the influence of specific game types and design features on ADHD symptoms and executive functioning. The findings showed moderate improvements in overall ADHD symptoms and small-to-moderate gains in executive outcomes. The study further suggests that intervention benefits may depend less on surface-level gamification features and more on the underlying cognitive demands and regulatory scaffolding embedded within the game design.