Purpose <p>To investigate the association between chronic upper airway inflammatory diseases, specifically chronic rhinosinusitis (CRS) and allergic rhinitis (AR), and the risk of glaucoma.</p> Methods <p>Two independent reviewers systematically searched PubMed and Embase through December 2025 to identify observational studies evaluating the association between CRS or AR and glaucoma. Risk of bias was assessed using the ROBINS-E tool. Risk estimates, including odds ratios and hazard ratios, as well as glaucoma incidence rates, were extracted. Pooled risk ratio (RR) for glaucoma was calculated using a random-effects model with inverse-variance weighting.</p> Results <p>Among 1,620 records identified, seven studies met the inclusion criteria, comprising a total of 83,557,354 individuals (three CRS studies and four AR studies), including five retrospective cohort studies, one case–control study, and one cross-sectional study. The incidence of open-angle glaucoma was 5.5 per 1,000 person-years in patients with CRS, while the incidence of glaucoma was 7.1 per 1,000 person-years in patients with AR. CRS was associated with a significantly increased risk of glaucoma (RR 1.49, 95% CI 1.25–1.79). AR was similarly associated with an elevated risk (RR 1.39, 95% CI 1.33–1.45). CRS and AR were associated with a higher risk of open-angle glaucoma and low-tension glaucoma (RR 1.47, 95% CI 1.32–1.63). In studies adjusting for corticosteroid exposure, the increased risk of glaucoma remained consistent (RR 1.37, 95% CI 1.29–1.48).</p> Conclusion <p>Both CRS and AR are associated with an increased risk of glaucoma, independent of corticosteroid use.</p>