ABSTRACT Aim Paediatric overweight and obesity are global health concerns linked to various physical and psychosocial challenges. Over the past decade, online games for exercise, exergames, have re‐emerged in homes and schools as a possible solution to encourage physical activity and address childhood overweight and obesity. However, evidence on their effectiveness remains limited. This systematic review aimed to analyse the effects of exergaming on body mass index and physical activity in children and adolescents. Methods Using keywords such as ‘child’, ‘adolescent’, ‘obesity’, ‘overweight’, ‘exergaming’ and ‘active video gaming’, a comprehensive search was conducted across PubMed and Embase, yielding 801 initial articles. Articles were screened following PRISMA guidelines and assessed using Covidence and Cochrane's quality assessment tools. Results Twelve articles met the inclusion criteria. Sample sizes ranged from 29 to 445 participants, with intervention durations from 2 to 48 weeks. The results indicated that exergaming showed a subtle to moderate effect on body mass index and promising effects on moderate to vigorous physical activity. Conclusion These findings suggest that exergames have potential as adjunctive tools in treating paediatric overweight and obesity. However, the limited number of studies and heterogeneity in the interventions highlight the need for further research in this field.