<p>The accessory maxillary ostium (AMO) is an anatomical variant implicated in sinus drainage dysfunction and chronic sinusitis. While previous studies have reported its prevalence, the relationship between AMO and adjacent anatomical structures remains poorly understood. This study aims to investigate the association between AMO presence and sinonasal anatomical variations, as well as its clinical correlation with sinus pathology. A prospective cross-sectional study was conducted on 60 patients (&gt; 18 years) with nasal symptoms, excluding trauma, tumors, or prior surgery. Paranasal sinus CT scans were analyzed for AMO presence, anatomical variations (agger nasi cells, Haller cells, deviated septum, etc.), and pathological changes (mucosal thickening, sinusitis). Data were analyzed using SPSS v28, with Chi-square tests determining associations (<i>p</i> &lt; 0.05 significant). AMO was identified in all patients, with unilateral occurrence in 53.3% (right 28.3%, left 25%) and bilateral in 46.7%. Significant associations were found between AMO and both mucosal thickening (76–93% prevalence, <i>p</i> = 0.046) and maxillary sinusitis (59–82% prevalence, <i>p</i> = 0.047). Bilateral AMO showed the strongest correlations with these pathologies. Agger nasi cells were highly prevalent (73–94%) but not significantly associated with AMO (<i>p</i> = 0.257). Other anatomical variations, including deviated nasal septum (89–94%) and nasal spur (53–61%), showed no significant association with AMO presence. This study demonstrates a significant association between AMO, particularly bilateral cases, and maxillary sinus pathology. The findings suggest that AMO may contribute to impaired sinus drainage and increased susceptibility to sinusitis. These results highlight the importance of recognizing AMO during diagnostic evaluation and surgical planning for chronic sinusitis.</p>