Background: Surgically assisted maxillary expansion has been used for the treatment of transverse maxillary deficiency in adult patients. The aim of this study is to evaluate, through a systematic review, the effect of this therapy on the dimensions of the aeropharyngeal dimensions and on the improvement of nasal ventilation. Materiel and method: 5 databases have been explored from 2010 (Pubmed, Scopus, Embase, Cochrane and Web of Science) using keywords expansion AND airway AND volum. After evaluating title, abstract and full text of articles found from databases, only 11 matching the inclusion criteria were included in the systematic review. Results: All the studies have shown that, in addition to its action on the maxillary bone, surgically-assisted maxillary expansion induces also an enlargement of the nasal floor and a reduction in airflow resistance, which promotes an improvement in nasal breathing. Conclusion: this surgical approach may lead to a modification in upper airway’s dimension and improvement of nasal ventilation.