Experimental studies suggest potential anti-obesity effects of non-digestible oligosaccharides (NDOs). This study aimed to evaluate the effect of NDO intake on body weight and other anthropometric parameters in overweight or obese adults through a systematic review and meta-analysis of RCTs. Multiple databases were searched for relevant randomised, controlled trials on NDOs and body weight or associated outcomes. Statistical pooling of data for meta-analysis was performed using the generic inverse-variance method with random-effects models. Nine trials were included post-screening (n = 455 participants). Increased intake of NDOs resulted in statistically significant reduction in body weight (MD=-0.87 kg [95% CI:-1.55,0.20], p = 0.01) and body fat (-1.56 kg [95% CI:-2.23,-0.89], p<0.00001) relative to control. A risk of bias assessment revealed potential for improvement in reporting/design of most trials. Increased intake of NDOs significantly reduced body weight and body fat in healthy, overweight and obese adults. This effect was modest and should therefore be interpreted cautiously.