The aim of this study was to provide a quantitative synthesis of the effects of randomized controlled pediatric lifestyle interventions in treating obesity among 11-17-year-old children. We conducted a systematic review and meta-analysis on the randomized controlled trials, consisting of actual exercise training and nutrition education, published between January 2000 and August 2022. The initial search yielded 2598 articles, with eight articles meeting the inclusion criteria. The articles were analyzed using a multivariate random effects model. The primary outcome variables were body mass index (BMI), standardized BMI (BMIz), and waist circumference (WC). Our analyses showed that lifestyle interventions were efficacious in improving BMI (-1.77 kg/m2, 95% CI [-2.70, -0.83], p< 0.001), BMIz (-0.30, 95% CI [-0.45, -0.16], p< 0.001), and WC (-3.32 cm, 95% CI [-5.35, -1.29], p <0.001) in children with overweight and obesity. In addition, moderation analyses suggested that the efficacy of the lifestyle interventions correlated positively with participants' weight status and was enhanced when an intervention was boosted with a longer intervention duration and higher frequency. In conclusion, the current evidence suggests that lifestyle interventions are efficacious in treating children with obesity. The available evidence further indicates that duration, frequency, along weight status, were moderating the effectiveness of these lifestyle interventions.