Objectives: We performed a meta-analysis of all of the available randomised controlled trials (RCTs) to investigate whether physical exercise contributes to weight loss or physical function improvement in adults receiving bariatric surgery. Methods: We searched PubMed, Embase, the Cochrane Library, OVID and the CINAHL up through May 2018. RCTs that assigned adults with obesity to either an exercise training group or a no-exercise group after bariatric surgery were included. The primary outcomes were weight loss and physical function. Study bias was assessed using the Cochrane risk of bias tool, and the quality of evidence was assessed using GRADEpro. Results: A total of eight studies met the inclusion criteria (n=347 participants). Most of the studies carried a low risk of bias due to randomisation and blinding. Compared with those without exercise intervention after surgery, patients engaging in physical exercise were associated with greater weight loss (weighted mean difference (WMD) -1.94 kg; 95% CI -3.18 to -0.69; n=8) and longer 6 min walk distance (6MWD; WMD29.67 m; 95% CI 25.97 to 33.37; n=2) during follow-up. By subgroup analyses, the additional weight loss in exercise group was related to the starting time and type of exercise: patients engaging in exercise 1 year or more after surgery and patients received aerobic-resistance exercise experienced more weight loss. Besides, patients in exercise training group also had lower systolic blood pressure and resting heart rate after surgery. The quality of evidence for these outcomes was moderate to very low. Conclusions: Physical exercise after bariatric surgery provides 1.94 kg additional weight loss and 29.67 m longer 6MWD compared with surgery alone. Moreover, engaging in exercise 1 year or more after surgery, and a combined aerobic and resistance training programme may result in greater weight loss.