Ovarian cancer is among the most lethal gynecologic malignancies, often diagnosed at advanced stages due to a lack of effective screening tools. Recent studies suggest that the platelet-to-lymphocyte ratio (PLR), an indicator of systemic inflammation, may serve as a potential biomarker for diagnosing and staging ovarian cancer. We conducted a systematic review and meta-analysis, adhering to PRISMA guidelines. We searched the PubMed/Medline, Scopus, Web of Science, and EMBASE databases. We pooled data using a random-effects model to assess the sensitivity, specificity, and diagnostic performance of PLR in ovarian cancer. The meta-analysis of 22 studies comprising 5740 participants showed significantly elevated platelet-to-lymphocyte ratio (PLR) values in ovarian cancer patients compared to healthy controls, with a mean difference of 46.84 (p < 0.001). Additionally, PLR demonstrated utility in distinguishing benign from malignant lesions and early-stage from advanced-stage ovarian cancer. While PLR shows potential as a cost-effective and accessible biomarker for ovarian cancer diagnosis and staging, its diagnostic accuracy remains moderate. Therefore, combining PLR with other diagnostic tools enhances clinical decision-making.