This work evaluates the use of respiratory oscillometry to identify the changes in lung mechanics due to idiopathic scoliosis and the association of these changes with the progression of the spine curvature. A total of 54 volunteers were analyzed, 15 in the control group, and 39 in the scoliosis group divided into three subgroups with angles of 10–45°, 46–70°, and above 70° of the Cobb angle, which evaluates spinal deformity. Increasing Cobb angle did not introduced significant changes in the resistive properties. In contrast, caused a significant increase in the resonance frequency (fr, ANOVA = 0.005) and in the area under the reactance curve (Ax, ANOVA = 0.008). A significant reduction in the dynamic compliance (Cdyn, ANOVA = 0.01) was also observed. Furthermore, correlation analysis showed a clear association among Cobb angle and worsening of reactive parameters (R = –0.55, p = 0.0003). These data are consistent with previously published results and physiological rationale, confirming the high potential of respiratory oscillometry in evaluating respiratory abnormalities in patients with scoliosis.