BACKGROUND Re-deviation of the nasal septum may occur after septoplasty. Because the cartilaginous septum grows until the age of 16-17 years, septoplasty is usually recommended thereafter. However, severely deviated septum may necessitate septoplasty in younger adolescents. OBJECTIVE To compare the incidence of re-deviated nasal septum in patients who underwent septoplasty at ≤18 versus ≥19 years of age. METHODS The medical records and endoscopic photographs of patients who underwent septoplasty between 2005 and 2015 were retrospectively reviewed. Re-deviation of the nasal septum was defined as >50% narrowing of one side of the nasal cavity compared to immediately after septoplasty. RESULTS The inclusion criteria were met by 52 adolescent patients and 549 adult patients. Re-deviation of the septum occurred in 11 (21.2%) and 39 (7.1%) patients, respectively; the difference was significant. Most patients had caudal and upper cartilaginous deviations. Four adolescent and 14 adult patients underwent revisional septoplasty. CONCLUSIONS Adolescent patients who underwent septoplasty had a significantly higher incidence of re-deviation of the nasal septum than adult patients. Therefore, when septoplasty is deemed necessary in adolescent patients, they and their parents should be informed about the possibility of re-deviation and the need for revisional septoplasty.