Pelvic incidence (PI) is a fundamental determinant of sagittal spinal alignment. The concept of PI–lumbar lordosis (LL) relationship has emerged as a key parameter in the assessment of sagittal balance, with growing evidence supporting its association with clinical outcomes. However, the relationship between PI with segmental LL especially on distribution of proximal lumbar lordosis (PLL) and distal lumbar lordosis (DLL) in adolescent idiopathic scoliosis (AIS) is not well established. The objective of this study is to determine the influence of PI, stratified into low, average and high groups on segmental lumbar lordosis and spinopelvic alignment in AIS. A retrospective analysis was performed on preoperative sagittal radiographic parameters of 506 AIS patients (Lenke 1–4). PI, global and segmental lumbar lordosis, sacral slope (SS), and pelvic tilt (PT) were measured. Patients were stratified into low (<45°), average (45°–60°), and high (>60°) PI groups. Segmental LL distribution and pelvic parameters were compared across PI groups. Pairwise comparisons of DLL distributions were performed using the Kolmogorov–Smirnov test. LL increased progressively from low to high PI groups (51.4°±10.7° vs 57.4°±10.9° vs 63.4°±10.8°; p<0.001), driven primarily by a corresponding increase in PLL (16.8°±8.4° vs 23.3°±9.3° vs 28.2°±8.3°; p<0.001). In contrast, DLL remained comparable across PI groups (p=0.507). Although there were no significant differences in DLL distribution between groups, the plotted data demonstrated distinct patterns. In the low PI group, the average DLL ranged from 30–34°. In the high PI group, the average DLL ranged from 35–39°. SS and PT increased progressively across PI groups (p<0.001). In conclusion, PI significantly influence the LL, PLL, SS and PT while the DLL remain relatively constant. These findings underscore the adaptive role of the proximal lumbar spine in accommodating sagittal balance. Restoration of lumbar lordosis (via rod contouring) should be carefully tailored to achieve an optimal distribution of proximal and distal lumbar lordosis according to the PI especially in AIS patients requiring distal lumbar fusion.