Background <p>The maxillary sinus exhibits significant anatomical variation, influenced by sex, age and laterality. Understanding these morphological characteristics is essential for effective diagnostic and surgical planning in dentistry and maxillofacial procedures. Comprehensive Comprehensive cone-beam computed tomography (CBCT)-based evaluations in Saudi populations remain limited.</p> Objective <p>This study aimed to assess maxillary sinus anatomical features and dimensions using CBCT imaging in a Saudi subpopulation, examining associations with sex, side and age.</p> Methods <p>A retrospective, cross-sectional analysis was conducted on 1018 CBCT scans (2036 sinuses) of adults aged ≥ 18 years, obtained between January 2024 and January 2025 at a leading dental centre in Ha’il, Saudi Arabia. Sinus parameters, comprising width, length, area, perimeter, septa, fluid, and mucosal thickening, were measured. Statistical tests evaluated associations with sex, age and laterality.</p> Results <p>Sinus fluid was the most frequent abnormality and was significantly more common in male and older adults (<i>p</i> &lt; 0.001). Sinus dimensions (width, length, area, perimeter) were significantly larger in male than in female (<i>p</i> &lt; 0.001) and decreased progressively with age, particularly after the fifth decade. Bilateral dimensions were strongly correlated (ρ &gt; 0.55, <i>p</i> &lt; 0.001), confirming anatomical symmetry.</p> Conclusions <p>Maxillary sinus morphology varied significantly with sex and age in this Saudi population. Male and younger individuals exhibited larger sinus dimensions, and sinus pathology was more common in older adults. These findings underscore the value of CBCT imaging for individualised treatment planning and highlight the need for population-specific anatomical references in clinical and forensic contexts. These findings have implications for surgical planning and sex estimation in forensic cases.</p>