AIM: This systematic review and meta-analysis was conducted to evaluate the efficacy and safety of 24 weeks of semaglutide treatment in patients with non-alcoholic fatty liver disease (NAFLD) or non-alcoholic steatohepatitis (NASH). METHODS: PubMed, Embase, Scopus, Cochrane CENTRAL, and ClinicalTrials.gov databases were searched for relevant studies. The primary outcome was the change in the serum alanine transaminase level. The secondary outcomes were changes in liver stiffness, liver function test parameters, metabolic parameters, and safety. Pooled mean differences and relative risks were calculated using random-effects models. RESULTS: Six hundred studies were screened and eight were included (n = 2413). Semaglutide treatment showed a reduction in serum alanine transaminase [mean difference: 14.07 U/L (95% CI: 19.39 to -8.75); p < 0.001] and aspartate transaminase [mean difference: 6.89 U/L (95% CI: 9.14 to -4.63); p < 0.001] levels. There was a significant improvement in liver fat content [mean difference: 4.97% (95% CI: 6.65 to -3.29); p < 0.001] and liver stiffness [mean difference: 0.96 kPa (95% CI: 1.87 to -0.04); p = 0.04]. There were significant improvements in the glycated hemoglobin level and the lipid profile. However, the risk of serious adverse events [relative risk: 1.54 (95% CI: 1.02 to 2.34); p = 0.04] was high following semaglutide treatment as compared to placebo; the most common ones were gastrointestinal (nausea and vomiting, dyspepsia, decreased appetite, constipation, and diarrhea) and gallbladder-related diseases. CONCLUSION: Treatment with 24 weeks of semaglutide could significantly improve liver enzymes, reduce liver stiffness, and improve metabolic parameters in patients with NAFLD/NASH. However, the gastrointestinal adverse effects could be a major concern.