Background/Objectives: Bilateral symmetry of craniofacial structures is a fundamental principle in clinical application, particularly in procedures involving unilateral trauma or skeletal loss. The zygomaticomaxillary suture (ZMS), located at the articulation between the zygomatic bone and maxilla, is considered a potentially stable midfacial landmark owing to its distinct anatomical position and relevance in surgical planning. This study aimed to evaluate the bilateral symmetry of the ZMS and its surrounding anatomical structures in healthy adults using three-dimensional CT reconstructions and to develop predictive models for contralateral estimation. Methods: Craniofacial CT scans of 200 adult individuals (101 females and 99 males, aged ≥18 years) were retrospectively analyzed. Fourteen morphometric parameters related to the ZMS and adjacent craniofacial structures were measured bilaterally on 3D reconstructions generated from CT data. Statistical analyses included tests for normality, sex and side comparisons, correlation analysis, and linear regression to develop side-predictive formulas. Results: No statistically significant differences were found between the right and left sides for any parameter, confirming a high degree of bilateral symmetry. However, significant sex-based differences were observed in two parameters: the lateral extension of the ZMS (p = 0.024 right; p = 0.046 left) and piriform aperture width (p = 0.017). Regression models developed for each sex provided reliable estimates of contralateral morphometric values based on single-sided measurements. Conclusions: The results confirm high bilateral symmetry of the ZMS and adjacent midfacial structures, supporting its reliability as a reference point in surgical planning and facial reconstruction. Regression models enhance the accuracy of mirror-based approaches in unilateral midfacial defects.