There has been growing recognition of the need for considering weight-loss strategies following metabolic bariatric surgery (MBS) to limit the magnitude of potential weight regain. The use of glucagon-like peptide-1 receptor agonists (GLP-1RAs) in this setting remains uncertain. We conducted a systematic review and meta-analysis to evaluate the effect of GLP-1RAs on weight changes in patients who previously underwent MBS. We examined the effect of GLP-1RAs on weight changes by calculating pooled estimates (random-effects model) of the absolute differences in body weight (kg) compared to baseline for observational studies and compared to a control group for randomized controlled trials (RCTs). A total of 17 studies (1164 participants) met our inclusion criteria. Pooling the data from the 14 observational studies evaluating the effect of GLP-1RAs post bariatric treatment demonstrated a reduction of 7.83 kg compared to pre treatment (before the use of GLP-1RA) (weight-7.83 kg [95% CI, -9.27 to -6.38]). With respect to tolerability, 23% (95% CI, 10%-36%) of participants reported any adverse event but only 7% discontinued treatment. Data from RCTs showed that the use of GLP-1RAs induced weight reduction of 4.36 kg (95% CI, -0.42 to -8.30) compared to placebo with a similar safety profile. Our findings suggest that the use of liraglutide and semaglutide in patients who previously underwent MBS can promote significant weight reduction with an acceptable safety profile.