Polycystic ovary syndrome (PCOS) is a common endocrine-metabolic disorder in reproductive-aged women, often associated with obesity and dyslipidemia. Semaglutide, a GLP-1 receptor agonist (GLP-1 RA), improves glycemic control and weight, but its effects on PCOS remain unclear. This meta-analysis evaluates semaglutide's impact on BMI and blood lipids in PCOS patients. We searched PubMed, Embase, Cochrane Library, ClinicalTrials.gov, WHO ICTRP, and gray literature sources for RCTs (2010-2025) comparing semaglutide vs. placebo/conventional treatment in PCOS patients. The outcomes included BMI, total cholesterol (TC), triglycerides (TG), LDL-C, and HDL-C. The data were analyzed using RevMan 5.4, with mean differences (MD) and 95% CIs were calculated. Heterogeneity was assessed via I². Eight RCTs (526 patients) were included. Semaglutide significantly reduced BMI (MD: -2.20 kg/m², 95% CI: -2.42 to -1.97, P < 0.001), TC (MD: -0.42 mmol/L, 95% CI: -0.46 to -0.39, P < 0.0001), TG (MD: -0.35 mmol/L, 95% CI: -0.38 to -0.32, P < 0.0001), and LDL-C (MD: -0.31 mmol/L, 95% CI: -0.35 to -0.27, P < 0.0001), but not HDL-C (P = 0.8524). Subgroup analysis showed greater efficacy at doses ≥ 1.0 mg/week and in patients with a baseline BMI > 28 kg/m². Overall evidence quality was moderate to low based on GRADE assessment. Semaglutide significantly improves BMI and lipid profiles in PCOS, particularly at higher doses, and in obese patients. Further long-term studies are needed to confirm safety and reproductive outcomes.