Background and Objectives: This study aimed to elucidate the relationship between nasal septal deviation (NSD) and upper lateral cartilage (ULC) collapse.Methods: We conducted a retrospective review of 142 paranasal sinus computed tomography scans from patients who had undergone septoplasty due to confirmed NSD. The ULC angle was measured on both the narrow and wide sides of the nasal cavities, and these measurements were compared to evaluate the extent of ULC collapse in relation to the degree of NSD and patient age. The correlation between the degree of NSD and the degree of ULC collapse was also analyzed.Results: The mean ULC angle was found to be 13.4°±2.7° on the narrow side and 14.3°±2.7° on the wide side, with a statistically significant difference between the two (p<0.001). When comparing caudal and non-caudal NSD patients, there was no significant difference in the degree of ULC on either side (p=0.166). When comparing the ULC angle between two age groups (≥50 vs. <50 years), the difference in ULC angles was significantly greater in the group of patients aged under 50 years (0.3°±3.8° vs. 1.1°±2.2°, p=0.014). There was a significant positive correlation between the degree of ULC collapse and the degree of septal deviation (r=0.214, p=0.01).Conclusion: NSD was associated with ULC collapse on the narrow side and a narrow internal nasal valve area. This result indicates that clinicians should check for concomitant ULC collapse in patients with NSD.