Purpose: Surgically Assisted Rapid Maxillary Expansion (SARME) is widely used to address transverse maxillary deficiency and associated malocclusion. However, SARME-induced structural changes in the nasal cavity can influence olfactory function. This study assessed the impact of SARME on olfactory outcomes and explored the relationship between those olfactory changes and extent of maxillary expansion. Methods: This prospective study included 28 adult patients (mean age: 26.6 ± 9.4 years; range: 18–53 years) who underwent SARME for transverse maxillary deficiency. Olfactory function was evaluated preoperatively and six months postoperatively using the Sniffin’ Sticks Test, which provided scores for odor threshold, discrimination, and identification. Patients were categorized into two groups based on the extent of maxillary expansion, as follows: limited (≤ 6 mm) and wide (> 6 mm). Statistical analysis was conducted to characterize changes in olfactory scores and assess their correlation with the extent of expansion. Results: SARME was shown to have a significantly positive effect on olfactory function, with the most notable enhancements observed in suprathreshold tests, such as odor discrimination and identification. Improvements in odor threshold scores, indicative of peripheral olfactory function, were more pronounced in patients that underwent limited expansion than in patients with wide expansion. Conclusion: Modifications to the nasal anatomy induced by SARME can enhance olfactory function in adults. Nonetheless, excessive maxillary expansion may hinder olfactory improvements by disrupting the nasal valve and compromising airflow dynamics. The extent of expansion should be optimized to balance improvements in nasal patency with the preservation of beneficial airflow characteristics.