The task of the present study was to investigate the relationship between parameters and factors predictive of voice quality and to suggest treatment guidelines for patients suffering from vocal polyps. In total, 158 patients diagnosed with vocal polyps and who received voice therapy were enrolled. Clinicomorphological factors such as size, location, color, and type of the polyp were evaluated. Perceptive and acoustic voice evaluation was conducted and the relationship of these voice parameters with clinicomorphological factors was analyzed. Additionally, factors favorable for voice therapy were investigated. GRBAS scale grade was closely related to acoustic parameters, such as jitter and shimmer. Univariate analysis showed the size of the polyp, the color of the vocal fold, a history of voice abuse, associated muscle tension dysphonia (MTD), and opposing reactive scar affected voice quality. In multivariate analysis, only the size of the polyp was associated with voice quality. The patients in whom the voice quality improved with voice therapy initially had smaller polyps and whitish-colored vocal folds. Results of the present study indicate that although the most influential factor on voice quality in vocal polyp patients was the size, several other factors should be considered in evaluating and treating vocal polyps. The size of the polyp and the color of the vocal fold are indicative of success or failure in voice therapy.