OBJECTIVE To evaluate the methodologic quality of 3 primary open-angle glaucoma (POAG) clinical practice guidelines (CPGs). DESIGN The CPGs were assessed with the Appraisal of Guidelines for Research and Evaluation (AGREE) II instrument. PARTICIPANTS Four authors (A.M.W., C.M.W., B.K.Y., D.J.W.) performed independent assessments of POAG CPGs. METHODS POAG CPGs published by the American Academy of Ophthalmology (AAO), Canadian Ophthalmological Society (COS), and National Institute for Health and Care Excellence (NICE) were appraised using the AGREE II instrument's 6 domains (Scope and Purpose, Stakeholder Involvement, Rigor of Development, Clarity of Presentation, Applicability, and Editorial Independence) and Overall Assessment score summarizing guideline quality across all domains. RESULTS Scores ranged from 28% to 85% for the AAO CPG, 51% to 96% for the COS CPG, and 55% to 97% for the NICE CPG. Intraclass correlation coefficients for the reliability of mean scores for the AAO, COS, and NICE CPGs were 0.89, 0.86, and 0.74; 95% CIs were 0.80 to 0.95, 0.74 to 0.93, and 0.51 to 0.87, respectively. The strongest domains were Scope and Purpose (AAO, COS, NICE) and Clarity of Presentation (COS, NICE). The weakest domains were Stakeholder Involvement (AAO, COS) and Editorial Independence (AAO, COS, NICE). CONCLUSIONS Future POAG CPGs can be improved by addressing potential conflicts of interest within the development group, ensuring transparency of guideline development methodology, and involving all relevant stakeholders in guideline development and review.