Obesity in the young is increasingly prevalent. Early, effective intervention is paramount. Treatment options are lifestyle modifications, pharmacological therapies, endoscopic treatments and bariatric surgery. However, the relative effectiveness of these treatments in young patients remains unclear. We systematically identify and meta-analyse studies evaluating weight loss treatments in young people (< 21 years) with obesity. From 16,372 identified studies, 83 were eligible for meta-analysis. Bariatric surgery resulted in high short/medium-term weight loss (pooled estimate 14.04 kg/m2). Lifestyle and pharmacological therapies impacted weight more moderately (pooled estimate 0.99 and 0.94 kg/m2 respectively). Due to its high efficacy, bariatric surgery should be considered earlier when treating obesity in young people. However, due to the invasiveness and inherent risks of bariatric surgery, all other weight loss routes should be exhausted first.