Background: As the pandemic of obesity presents an increasing serious health challenge worldwide, additional medical interventions, especially pharmacotherapy, should be addressed for the affected people. Liraglutide 3.0 mg, is one of the possible options for long-term anti-obesity treatment. Research design and methods: We systematically searched the databases of PubMed, Embase, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov. A meta-analysis was then performed using random-effect models. Results: Meta-analyses of seven phase 3 and 4 RCTs (N = 6,028), which were conducted in adults with obesity or overweight for at least 1 year, demonstrated a significant weight reduction with liraglutide 3.0 mg (mean difference of percentage weight change −4.81%; 95% CI: −5.56% to −4.06%; P < 0.00001), relative to placebo. However, more participants taking liraglutide experienced at least one adverse event. More discontinuations due to adverse events were observed among them. In the subgroup analysis among participants with or without diabetes mellitus (DM), pooled result showed that liraglutide was associated with a greater decrease in the percentage of weight change in participants without DM. Conclusions: This study provided support for the use of liraglutide 3.0 mg for weight management in adults with obesity or who are overweight. © 2022 Informa UK Limited, trading as Taylor & Francis Group.