Objective:The purposes of this study were to determine the midpalatal suture (MPS) opening depth and to assess its relation with the zygomaticomaxillary suture (ZMS) by age with using cone beam computed tomography (CBCT).Materials and Methods:In this cross-sectional study, 167 CBCT scans of patients aged 7–25 years (mean age: 16.04 ± 5.17 years) were selected based on predefined criteria and categorized into four age groups. The mean percentages of the depth of MPS opening at anterior, middle, and posterior regions in the coronal and closure status of ZMS in axial views were determined by a maxillofacial radiologist.Results:The mean percentages of MPS opening depth at anterior, middle, and posterior regions were 98.20%, 89.27%, and 71.44%, respectively. In these regions, 20–25-year age group showed a significant difference compared with first- and second-age groups. A significant difference was observed in the frequencies of complete MPS opening in different age groups in the middle (P = 0.017) and posterior (P = 0.001) regions. About 80.20% patients had open ZMS bilaterally. The percentages of opening depth in the three regions were 97.8%, 91.8%, and 75.6%, respectively, when ZMS was open on both sides.Conclusion:Percentage of opening depth of this suture decreased by age. MPS closure starts from the posterior region. ZMS in younger people is usually open on both sides; however, it can be closed on one or both sides by age. An association was observed between bilateral closure or opening of ZMS and mean percentage of MPS opening in the middle and posterior regions.