"Purpose: This study was done to test structural equation modeling of health-related quality of life (QOL) of men with obstructive sleep apnea in order to identify parameters affecting QOL and provide guidelines for interventions and strategies to improve QOL in these patients. Methods: Model construction was based on ‘The conceptual model of patient outcome in health-related QOL’ by Wilson and Cleary, using the variables; age, physiological factors, social support, cognitive appraisal, symptoms and QOL. Participants were 201 adult male patients recruited at a tertiary university hospital in Seoul. Data were collected via questionnaires, polysomnography, and clinical records. Results: Age and symptoms directly influenced QOL. Social support and cognitive appraisal about sleep did not have a direct influence on QOL, but indirectly affected it via symptoms. QOL was lower in patients who were younger and had more severe symptoms. Symptoms were more severe for patients with lower social support and more dysfunctional cognitive appraisal. When social support was lower, cognitive appraisal was more dysfunctional. Conclusion: These results suggest it is necessary to not only manage symptoms, but also apply interventions to increase social support and cognitive appraisal about sleep in order to increase QOL in patients with obstructive sleep apnea."