Objective To assess the long-term effects of velopharyngeal surgery on objective and subjective symptoms in patients with obstructive sleep apnea (OSA). Study Design Prospective cohort study. Setting University medical center. Subjects and Methods Eighty-six patients with OSA underwent velopharyngeal surgery, which consisted of revised uvulopalatopharyngoplasty with uvula preservation, with or without concomitant transpalatal advancement pharyngoplasty. The results from polysomnography and the Epworth Sleep Scale after 6 months and 5 years were compared with baseline. Baseline variables were compared between responders and nonresponders. Results Sixty-three patients were successfully followed up at the end of study. The surgical success rate after 6 months and 5 years was 66.67% (42 of 63) and 60.32% (38 of 63), respectively, with no significant difference (P = .459). The apnea-hypopnea index and Epworth Sleep Scale dramatically decreased from baseline after 6 months and 5 years in responders and nonresponders (P < .001 for all). As compared with nonresponders, the responders exhibited larger tonsil size, higher nocturnal lowest oxygen desaturation, lower CT90 (percentage of time with oxygen saturation <90%), and shorter MH (vertical distance between the lower edge of the mandible and hyoid in the midsagittal plane of computed tomography). Tonsil size and CT90 showed significant predictive value for surgery success (P < .001 for both). Conclusion Velopharyngeal surgery was effective in improving nocturnal respiration and excessive daytime sleepiness in patients with OSA at 6-month and 5-year follow-up. Tonsil size and CT90 could be predictors for surgery responders.