Introduction: Glucagon-like peptide 1 receptor agonist (GLP-1 RA) is a class of hypoglycemic medications. Semaglutide once-weekly (QW) and liraglutide once-daily (OD) significantly improved glycemic control compared to placebo. To date, no long-term phase III trials directly comparing semaglutide and liraglutide are available. This network meta-analysis (NMA) aims to compare the long-term efficacy of semaglutide and liraglutide. Methods: PubMed, Embase, and Cochrane Library were searched from inception until June 2019 to identify relevant articles. Nine long-term randomized controlled trials comparing once-weekly semaglutide or liraglutide with placebo or other active comparisons were identified. The outcomes of interest were changes in HbA1c and weight after 52 weeks. A Bayesian framework and NMA were used for data synthesis. This is a sub-study of the protocol registered in PROSPERO (number CRD42018091598). Results: The data showed significant superiority in HbA1c reduction of semaglutide 1 mg QW over liraglutide 1.2 and 1.8 mg with a treatment difference of 0.47% and 0.3%, respectively. Semaglutide 0.5 mg QW was found to be significantly superior to liraglutide 1.2 mg in HbA1c reduction with a treatment difference of 0.17%. Regarding weight reduction analysis, semaglutide 0.5 and 1 mg QW were significantly associated with a greater reduction than liraglutide 0.6 mg with a treatment difference of 2.42 and 3.06 kg, respectively. However, no significant reduction was found in comparison to liraglutide 1.2 and 1.8 mg. Conclusions: Semaglutide improved the control of blood glucose and body weight. The capacity of long-term glycemic control and body weight control of semaglutide appears to be more effective than other GLP-1 RAs, including liraglutide. However, considering the number of included studies and potential limitations, more large-scale, head-to-head, well-designed randomized-controlled trials (RCTs) are needed to confirm these findings.