BACKGROUND: This study aimed to determine maxillary sinus volume (MSV) in different skeletal malocclusion classes and the correlation between MSV and craniofacial morphology on Cone Beam Computed Tomography (CBCT). MATERIALS AND METHODS: The study was performed retrospectively on CBCT images of individuals aged 12-24. A total of 129 patients (70 females, 59 males) with a normal vertical growth pattern (27° ≤ SNGoMe ≤ 38°) were divided into three groups according to malocclusion. Group 1 consisted of Class I (1 ≤ ANB ≤ 4) (n = 46) patients, Group 2 consisted of Class II (ANB >
4) (n = 47) patients, and Group 3 consisted of Class III (ANB <
1) (n = 36) patients. Four angular (SNA, SNB, ANB, SNGoMe) and linear (S-N, ANS-PNS, S-Ar, N-ANS) parameters were measured to evaluate craniofacial morphology. Right and left MSV were measured using Dolphin 11.0 (Dolphin Imaging, Chatsworth, CA, USA) imaging software. Pearson's correlation analysis was performed to assess statistical correlation. RESULTS: MSV was larger in males than females (male AMSV = 14,244.1 ± 4,735.8, female AMSV = 12,778.2 ± 4,606.9 p = 0.011) in the general population, but just the Class II group showed this (male AMSV = 16,089.6 ± 4,330.4, female AMSV= 12,705.9 ± 3,210.2, p = 0.008). RMSV and LMSV were similar (female p = 0.181 male p = 0.097), and MSV showed no significant differences between the different malocclusion classes in both sexes (female p = 0.315, male p = 0.118). In the Class III group, SNB was positively correlated with RMSV (r = 416, p = 0.012). MSV showed a significant positive correlation with N-ANS in all groups (Class I r = 0.359, p = 0.014, Class II r = 0.336, p = 0.021, Class III r = 0.387, p = 0.02). In the Class II and Class III groups, there was a statistically significant correlation between MSV and the S-N parameter (Class II r = 0.304, p = 0.038, Class III r = 0.412, p = 0.013). ANS-PNS parameter was measured at the lowest statistically significant level (female 43.1 ± 3.9a, p <
0.002, male 43.1 ± 4.3a, p <
0.002) in the Class III group, but no correlation was found with MSV. Only the Class II group showed a weak positive correlation between MSV and ANS-PNS (r = 0.314, p = 0.032). CONCLUSIONS: There was no difference regarding MSV between malocclusion classes. Class II males exhibited significantly larger MSV compared to females. There was a correlation between MSV and SNB, S-N, N-ANS and ANS-PNS parameters for various orthodontic skeletal patterns. Further studies are needed tounderstand the relationship between MSV and different skeletal structures.