SummaryThis overview of reviews synthesizes the effectiveness of obesity prevention interventions in children and adults on BMI/zBMI, following JBI and Cochrane Handbook guidelines. The protocol was prospectively registered in OSF in September 2020. Searches for eligible reviews were run in five databases and gray literature in May 2022. Systematic reviews published in 2010 and assessed BMI/zBMI outcomes of obesity prevention interventions were eligible. Screening, data extraction, and quality assessment were performed independently and in duplicate using standardized tools. For similar interventions, the more recent, higher‐quality review was included. Thirty reviews reporting on 60 discrete interventions (i.e., a specific intervention component), mapped to 14 of 21 IOM sub‐domains, were included. Nine interventions were classified as effective in improving BMI outcomes, including digital health or counseling interventions for adults in ‘healthcare environments’, behavioral interventions for children (broadly nutrition education), physical education curriculum modifications, and policies targeting food and beverages in ‘School environments’. This review extends on previous reviews by consolidating evidence from high‐quality, recent reviews to identify effective intervention components. Thus, this review provides direction for implementation efforts and highlights research gaps, where future research is warranted. However, as primary studies were not directly analyzed, gaps may reflect a lack of systematic reviews rather than primary research.