Previous studies have reported that migraine headaches may be one of the possible risk factors for open-angle glaucoma (OAG); however, a consensus has not been reached regarding the association between OAG and migraine. In this study, we examined the risk of developing OAG in migraine patients using a 12-year nationwide cohort. In this study, data from the Korean National Health Insurance Service-National Sample Cohort database from 2002 to 2015 was used to perform a retrospective cohort study. The study included 1,103,302 subjects, out of which 41,148 were diagnosed with migraine during 2003-2008 and were categorized as the migraine group, while 205,741 patients were selected as controls through propensity score matching at a 1:5 ratio. Subjects with migraine or OAG was ascertained based on KCD code. Multivariate Cox regression analysis was used to evaluate the hazard rate of OAG onset in the migraine group, and subgroup analysis was performed to identify any differences based on sex and age. Multivariate Cox regression analysis showed that the incidence of OAG was significantly greater among patients with migraine than among patients in the comparison group (hazard ratio [HR] 1.238; 95% confidence interval [CI] 1.160-1.132, P < 0.001). Moreover, the risk of developing OAG compared to subjects without migraine did not differ according to the presence of an aura (migraine with aura: HR 1.235; 95% CI 1.137-1.342, P < 0.001; migraine without aura: HR 1.248; 95% CI 1.143-1.363, P < 0.001). In subgroup analyses, the patients with migraine under 40-year-old were found to have a greater hazard rate (HR 1.576, 95% CI: 1.268-1.957) of developing OAG in contrast with patients with migraine and over 40-year-old (HR 1.167, 95%CI: 1.089-1.250) when compared to the corresponding non-migraine patients. This study showed that migraine is a significant risk factor for OAG onset in Korean population, and the presence of aura did not affect the hazard rate of OAG development. Patients with migraine showed significantly increased risk of developing OAG in Korean population, without significant differences according to the presence of aura. Our results suggest presence of migraine as a possible risk factor for OAG.