PURPOSE: The objective of this nationwide population-based cohort study was to determine the association between habitual alcohol consumption and the incidence of newly diagnosed obstructive sleep apnea (OSA). METHODS: This study used data from the Korean National Health Insurance Service database and included individuals aged ≥ 40 years who underwent a health check-up in 2011 or 2012. Individuals with a prior history of sleep apnea were excluded. Habitual alcohol consumption was defined as a weekly alcohol intake greater than 0 g. The study outcome was the newly identified cases of OSA, which we evaluated using the Cox proportional hazards regression model. RESULTS: A total of 3,988,993 individuals (mean age, 54.5 years; male, 50.1%; mean body mass index [BMI], 24.0 kg/m²) were included, of whom 1,688,094 (42.3%) had habitual alcohol consumption. During a mean follow-up period of 9.7 years, 33,563 new cases of OSA were documented. Individuals with habitual alcohol consumption had an incidence rate of 108.9 per 100,000 person-years, whereas those without habitual alcohol consumption had a rate of 69.6 per 100,000 person-years. Following adjustment for covariates including age, sex, BMI, income, smoking status, physical activity, and the Charlson comorbidity index, the hazard ratio for incident OSA was 1.026 (95% confidence interval, 1.001–1.051). The association between habitual alcohol consumption and incident OSA was more prominent among males and those with underlying chronic kidney disease or a history of cancer. CONCLUSION: This large-scale Korean population-based cohort study revealed that habitual alcohol consumption is associated with an increased incidence of OSA.