Introduction: The mandibular symphysis (MS) morphology results from the interplay of different genetic, non-genetic, vertical jaw relationships, inclination of the lower incisors and adaptive factors. The thickness of the alveolar process at the mandibular symphysis can be influenced by the facial growth pattern so the present study was designed to evaluate the (MS) dimensions in different vertical and horizontal jaws relationships. Material and Methods: A sample of 120 patients with age range from 11 to 13 years was divided into 6 groups according to ANB angle and SN to MP angle (CI: ANB between 0° and 4°; CIIDI ANB over 5°; CIII below 0°. Hypo-divergent: SN to Mp less than 29°. Hyper-divergent SN to Mp more than 36°). For each patient a CT of MS in the mid-sagittal plane was taken: (MS) widths, height and different inclination angles were measured by the CT machine integrated program. Results: hyper-divergent growth pattern showed highly significant differences between Class I, Class IID1 and Class III regarding perpendicular distance from Pg point to Id-Me line and the anterior inclination angles of the symphysis with Class III showed greater values than Class I and Class IID1 while the middle symphysial width showed high significant difference between Class I and (Class IID1, Class III). Hypo-divergent growth pattern showed high significant differences between Class I, Class IID1 and Class III regarding perpendicular distance from Pg point to Id-Me line and the anterior inclination angles of the symphysis with Class IID1 showed the lowest values for the inclination angles while Class I showed the shortest distance from Pg point to Id-Me line. Conclusion: Significant differences were found between hypo and hyper divergent growth patterns regarding all MS dimensions except Id-B distance and upper symphysial width (Id-Id1) and Class III showed the greater inclination angles than Class I and Class IID1.