Background <p>Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder characterized by cognitive deficits in areas such as attention, working memory, and executive function. Traditional treatments often address behavioral symptoms but may not fully target cognitive impairments. Game-based interventions (GBIs) have emerged as potential tools to enhance cognitive performance in children and adolescents with ADHD.</p> Methods <p>This systematic review and meta-analysis evaluated the efficacy of GBIs in improving cognitive outcomes in children and adolescents with ADHD. A comprehensive search of databases, including PubMed, Medline, PsycINFO, Web of Science, and Cochrane Library, identified 20 randomized controlled trials (RCTs) with 1,376 participants. Studies were included based on cognitive performance measures such as attention, metacognition, and executive function. Standardized Mean Differences (SMD) were calculated, and subgroup analyses were conducted based on intervention modality, session length, duration, and setting.</p> Results <p>The meta-analysis revealed a moderate overall effect size of GBIs on cognitive performance (SMD = 0.42, 95% CI: 0.143 to 0.697, <i>p</i> &lt; 0.01), with large heterogeneity (<i>I</i>² = 86.6%). Significant improvements were observed in attention (SMD = 0.724), cognitive flexibility (SMD = 0.565), and working memory (SMD = 0.486). However, effects on inhibitory control and metacognition were less pronounced.</p> Conclusion <p>GBIs show moderate efficacy in enhancing cognitive functions, particularly attention, cognitive flexibility, and working memory, in children and adolescents with ADHD. However, these findings should be interpreted with caution due to the substantial heterogeneity across studies. Future research could prioritize standardized outcome measures and multicentre RCTs across diverse cultural contexts to strengthen the evidence base.</p> Clinical trial number <p>Not applicable.</p>