We conducted a retrospective study to evaluate the short-term effect of uvulopalatopharyngoplasty (UPPP) on changes in the nasalance of five vowels: /a/, /ε/, /i/, /ɔ/, and /u/. Our study group was made up of 20 patients-15 males and 5 females, aged 16 to 57 years (mean: 37.3 ± 11.5)-who had undergone UPPP as a treatment for mild to moderate obstructive sleep apnea. Nasometry was used to obtain nasalance scores in all patients on the morning of the operation (day 1) and subsequently on day 4 or 5 (mean: 4.5 ± 0.5). Preoperatively, nasalance scores were highest for /i/ (mean: 29.8 ± 12.6) and /a/ (mean: 24.1 ± 10.3). After the operation, nasalance scores for all five studied vowels increased; they were highest for /i/ (mean: 40.7 ± +17.8) and /ε/ (mean: 30.0 ± 10.8). The increases in the nasalance of /i/, /ε/, and /u/ were statistically significant (p < 0.05). Our findings indicate that UPPP has a significant impact on nasalance immediately after surgery.