Objectives This study aimed to compare crestal facial bone measurements obtained from ultrasonography (USG) and cone-beam computed tomography (CBCT). Methods A total of 200 teeth from 15 systemically healthy individuals were included. Teeth were categorized as maxillary anterior (n=50), maxillary posterior (n=50), mandibular anterior (n=50), and mandibular posterior (n=50). Marginal bone level (MBL) and facial bone thickness at 1mm (MBT-1), 2mm (MBT-2), and 3mm (MBT-3) apical to the bone crest were measured using both USG and CBCT. USG imaging utilized an 18MHz transducer in B-mode, with standardized settings. Measurements were repeated twice by 2 independent examiners to assess intra- and inter-observer reliability. Interclass correlation coefficients (ICCs) and Bland-Altman plots were used for statistical comparisons. Results The ICCs between examiners ranged from 0.812 to 0.980. MBL, MBT-1, and MBT-2 measurements between ultrasound and CBCT readings showed excellent agreement (ICCs>0.75). The agreement for MBT-3 in mandibular anterior was fair (ICC: 0.528). Overall, mean difference between the 2 methods for MBL was 0.06mm and for MBT-1 was 0.018mm, without systematic bias. Conclusions Ultrasound can be a valuable and reproducible tool for MBL and MBT-1 measurements, and it can serve as an alternative to CBCT. Despite reasonable agreement in MBT-2 and MBT-3, potential variability should be considered. Advances in knowledge While widely used for soft tissue measurements, USG has limited application in marginal alveolar bone assessment in living humans. This study demonstrates the potential use of USG in the evaluation of facial marginal alveolar bone in different regions of the oral cavity.