Background and Objective: Reducing social inequalities of overweight and obesity in adolescents is a public health priority. Several interventions are implemented to overcome these inequalities, but their effectiveness is challenged. This study aimed to examine the effectiveness of interventions to reduce social inequalities of overweight and obesity in adolescents through a systematic review and a meta-analysis. Methods: A systematic search of all randomized control trials and quasi-experimental studies aiming to reduce social inequalities of weight in adolescents was conducted in five electronic databases. The primary outcome was social inequalities in Body Mass Index [BMI] z-score and the secondary outcomes were social inequalities in BMI, waist circumference, percent body fat and prevalence of overweight/obesity. Interventions were effective when they reduced social inequalities in at least one obesity-related outcome. Pooled difference means or Odds Ratios (OR) and their 95% Confidence limits (CI) were estimated for each outcome by using random effect models on Review Manager 5 software. The review is registered on PROSPERO (CRD42022362952). Results: This review included 38 publications from 33 studies. In these studies, interventions were universal (n=3), or proportionate (n=1) or targeted disadvantaged adolescents (n=29) and mostly underpinning the social cognitive theory (n=16). Interventions were effective in half of included studies (n=19, 57.6%). A meta-analysis (27 studies) revealed that targeted interventions reduced significantly adolescent’s BMI z-score (beta= -0.04; CI= [-0.08, -0.01]), BMI (beta= -0.32; CI= [-0.47, -0.18]), waist circumference (beta= -0.84; CI= [-1.48, -0.21]), unlike percent body fat and prevalence of overweight and obesity. Universal interventions did not reduce these inequalities. Conclusions: This review shows moderate effectiveness of interventions targeting disadvantaged adolescents in the reduction of social inequalities of overweight and obesity whereas universal scarce interventions are not effective. Then, high quality research with a better implementation to reach their full potential is required to strengthen the evidence.