This study aimed to compare alveolar bone thickness in anterior jaw regions in subjects with class I and class II malocclusions. Fifty cone beam computed tomography (CBCT) scans of the upper jaw and 20 CBCT images of the lower jaw were selected from available records in a private radiology center. The images were divided into class I and class II malocclusions, according to ANB and Wits analysis. Bone thickness was measured in the anterior regions of the maxilla and mandible in three areas including apex, middle root and alveolar crest at both buccal and lingual sides. The values were compared between groups using independent samples t-test and Mann�Whitney U test.In the upper jaw, bone thickness was significantly greater in class II than in class I patients in the palatal crest and buccal apex areas (P = 0.049 and P< 0.001, respectively). At the palatal side of the apex, the mean bone thickness was significantly lower in class II than in class I subjects (P = 0.001). Neither in other regions of the upper jaw nor at any part of the lower jaw, there was any significant difference in bone thickness between class I and class II patients (P > 0.05). The crest region of lower incisors was thin (<1mm) in both groups.There are some differences in alveolar bone thickness between class I and class II patients in the upper jaw, which should be considered in orthodontic diagnosis and treatment planning.