BACKGROUND: With rising concerns over physical inactivity in children and adolescents, gamified digital exercise interventions have emerged as promising strategies to enhance engagement and adherence to physical activity (PA). However, their overall effectiveness and the key behavior change techniques (BCTs) that drive success remain unclear. METHODS: This systematic review will assess the effects of gamified and digital exercise interventions on PA and health outcomes in children and adolescents aged 6-18 years. We will include randomized controlled trials and non-randomized studies of interventions focusing on interventions using digital technologies such as exergames, mobile applications, virtual reality, augmented reality, and wearables, with at least one gamification element. A comprehensive search will be conducted in PubMed, Web of Science, Scopus, Embase, CINAHL, PsycINFO, Cochrane Library, IEEE Xplore, CNKI, and Wanfang Data, covering studies from January 2014 to August 2025. BCTs will be categorized using the BCT Taxonomy v1 (BCTTv1), and data will be synthesized through meta-analysis or narrative synthesis depending on study homogeneity. The Promise Ratio will be used to identify the most effective BCTs. CONCLUSION: This review will provide valuable insights into the effectiveness of gamified and digital exercise interventions, helping to identify key BCTs that contribute to successful outcomes. The findings will guide the design and optimization of future exercise interventions among children and adolescents, with the goal of improving their overall health and well-being. PROSPERO REGISTRATION NUMBER: CRD420250651337.