Background: The pathophysiology of polycystic ovary syndrome (PCOS) is complex and heterogeneous. This systematic review and meta-analysis aimed to determine the triglyceride–glucose index and lipid ratios in women with and without PCOS. Methods: Literature searches were performed in PubMed, Scopus, Web of Science, Scielo, and Embase for studies reporting the triglyceride–glucose index and total cholesterol/high-density lipoprotein (HDL)-cholesterol, triglyceride/HDL-cholesterol, and low-density lipoprotein (LDL)-cholesterol/HDL-cholesterol ratios. Results are reported as standardized mean differences (SMDs) along with their 95% confidence intervals (CIs). Results: The search identified 61 observational studies, including case–control (n = 37), cohort (n = 2), and cross-sectional (n = 22) studies reporting results of interest according to different PCOS diagnosis criteria. Compared...