Purpose <p>This study aimed to examine pelvic morphology differences between adolescents with and without AIS, investigate variations among AIS patients with different scoliosis degrees and segments, and identify factors influencing pelvic rotation and tilt in relation to scoliosis.</p> Methods <p>Imaging data from 213 AIS patients and 187 normal adolescents were analyzed using the Caldwell-Moloy pelvic morphology classification. Differences in pelvic morphology were compared, and Cobb angle, vertebral rotation, pelvic rotation, and coronal pelvic tilt were measured and correlated.</p> Results <p>The non-scoliotic group had the highest percentage of Gynecoid-type pelvises (35.3%) and the lowest Platypelloid-type pelvises (14.5%). The AIS group had the highest Gynecoid-type pelvises (52.6%) and the lowest Anthropoid-type pelvises (8.9%). Significant differences were found between the groups (<i>P</i> &lt; 0.001). Pelvic morphology varied among AIS patients with different scoliosis degrees (<i>P</i> = 0.006) but not segments (<i>P</i> = 0.554). Cobb angle correlated with vertebral rotation (<i>P</i> &lt; 0.001).</p> Conclusion <p>Pelvic morphology significantly differs between AIS and non-scoliotic adolescents. These descriptive findings suggest a possible relationship between spinal deformity and pelvic structure. Further longitudinal or mechanistic studies are needed to determine whether pelvic morphology plays a role in AIS screening, progression monitoring, or treatment planning.</p>