Objective To evaluate lower incisor position and bony support between patients with Class II average- and high-angle malocclusions and compare with the patients presenting Class I malocclusions. Methods CBCT records of 79 patients were divided into 2 groups according to sagittal jaw relationships: Class I and II. Each group was further divided into average- and high-angle subgroups. Six angular and 6 linear measurements were performed. Independent samples t-test, Kruskal-Wallis, and Dunn post-hoc tests were performed for statistical comparisons. Results Labial alveolar bone thickness was significantly higher in Class I group compared to Class II group ( p = 0.003). Lingual alveolar bone angle ( p = 0.004), lower incisor protrusion ( p = 0.007) and proclination ( p = 0.046) were greatest in Class II average-angle patients. Spongious bone was thinner ( p = 0.016) and root apex was closer to the labial cortex in high-angle subgroups when compared to the Class II average-angle subgroup ( p = 0.004). Conclusions Mandibular anterior bony support and lower incisor position were different between average- and high-angle Class II patients. Clinicians should be aware that the range of lower incisor movement in high-angle Class II patients is limited compared to average- angle Class II patients.