Précis: There is a high rate of nonadherence to ocular hypotensive medications in a highly prevalent glaucoma setting, which warrants the attention of caregivers so as to inform their discussion of the possible barriers to adherence with their patients.Purpose: To assess adherence to ocular hypotensive medication objectively among glaucoma patients in Ghana and to identify factors associated with adherence. Materials and Methods:The prospective, observational cohort study included consecutive patients with primary open angle glaucoma treated with Timolol at the Christian Eye Centre, Cape Coast, Ghana. Adherence was assessed using Medication Event Monitoring System (MEMS) for a period of 3 months. MEMS adherence was defined as the number of doses taken divided by the number of doses prescribed, expressed in percent. Patients with adherence of 75% or less were classified as nonadherent. Associations with glaucoma medication self-efficacy, eyedrop-taking behaviors, and health beliefs were also assessed.Results: Of the 139 patients (mean age, 65 y [SD, 13 y]) included in the study, 107 (77.0%) were nonadherent when assessed with MEMS, compared with only 47 (33.8%) who self-reported being nonadherent. Overall, mean adherence was 48.5% ± 29.7. In univariate analysis, MEMS adherence was significantly associated with educational level (χ 2 = 9.18, P = 0.01) and the number of systemic comorbidities (χ 2 = 6.03, P = 0.049). Conclusion:Overall, mean adherence was low, and adherence was associated with educational level and number of systemic comorbidities in univariate analysis.