Objectives: To investigate the effects of Class I, II, and III malocclusions on upper airway (UA) volume and shape in adult normal mandibular position subjects using a medical imaging technique (CBCT). Methods: This cross-sectional study recruited 60 adults (20 per group) with Class II and III skeletal malocclusions (SM) and a normal sagittal mandibular position (Class I) between November 2024 and April 2025 at the Radiology Laboratory, Dental Clinic, College of Dentistry, University of Sulaimani, Sulaymaniyah, Iraq. The 3D images of the upper airway were obtained via CBCT, and the volumes of the nasopharynx, oropharynx, and hypopharynx were measured and statistically compared. Results: Among individuals, 35 were women, and 25 were men, yielding a gender ratio of 1.4:1. Ages ranged from 19 to 38 years, with a mean of 28.82 ± 5.87 years. The nasopharyngeal volumes for Class III patients were significantly larger (12.97 ± 2.04 cm³) compared to Class I (8.96 ± 1.55 cm³) and Class II (7.89 ± 0.96 cm³) (p < 0.001). Significant differences were reported between the oropharynx and hypopharynx, with the most essential volumes in Class III patients, who had a higher prevalence of elongated airway morphology (35%). In contrast, Class II patients had a higher proportion of collapsed airway morphology (15%). Conclusions: Skeletal malocclusions in Class III are associated with larger nasopharyngeal, oropharyngeal, and hypopharyngeal volumes than in other classes, reflecting anatomical associations rather than causation.