Aim: This study aimed to analyze the upper airway dimensions in adult patients with different anteroposterior (sagittal) skeletal malocclusions (class I, II, and III) using cone beam computed tomography (CBCT) imaging. Materials and methods: This retrospective cross-sectional study involved 90 CBCT records from adult subjects who were categorized into three skeletal groups based on their ANB values: Class I (n = 30), class II (n = 30), and class III (n = 30) and were evaluated. The following upper airway measurements were considered: oropharyngeal airway volume, hypopharyngeal airway volume, pharyngeal airway volume, oropharyngeal airway length, hypopharyngeal airway length, pharyngeal airway length, the most constricted site of the pharyngeal airway, and the most constricted cross-sectional area (MIN-CSA) of the pharyngeal airway. Additionally, the volume of the intraoral airway was determined. Pearson's correlation test was employed to evaluate the relationship between age and upper airway dimensions. Results: Significant differences in upper airway volume were found among skeletal groups in the hypopharyngeal (p = 0.034) and pharyngeal (p = 0.004) regions, with class III patients showing larger volumes compared to class II. Oropharyngeal (p = 0.044) and pharyngeal (p = 0.011) lengths were shorter in class III than in class I. In contrast, the narrowest cross-sectional area of the pharyngeal airway was larger in class III compared to class II (p = 0.003) and class I (p = 0.032). Class III patients had a significantly greater intraoral space volume than class II patients (p = 0.036). Conclusions: The present study found significant differences in upper airway dimensions among adults with varying maxillomandibular sagittal relationships. Class III patients had larger hypopharyngeal and pharyngeal volumes, but shorter oropharyngeal and pharyngeal lengths compared to other classes. The narrowest pharyngeal area was larger in class III, with gender and age also influencing airway dimensions. Clinical significance: These findings underscore the need to consider skeletal relationships, gender, and age in airway assessments. Accordingly, these factors can help clinicians better understand the correlation between airway dimensions and jaw position for accurate diagnosis and treatment planning of orthodontic and surgical interventions.