Introduction: Rapid maxillary expansion (RME) increases oxygen saturation in children with Obstructive Sleep Apnea (OSA) in the short and long term.

Objective: To analyze the current literature about rapid maxillary expansion, its effects on anatomical structures, midpalatal suture opening (MPS) and obstructive sleep apnea.

Methodology: Articles published at MEDLINE/PubMed and Science Direct were analyzed, with an emphasis on the last 5 years. Articles were evaluated with the PRISMA and AMSTAR guidelines. The search was carried out using the words "rapid maxillary expansion", "therapy" and "children".

Results: RME increases the transverse dimension of the maxillary bone, the nasal cavity, and the distance between zygomatic bones and mandibular condyles. It promotes the opening of the MPS, whose ossification is variable, that’s why in children older than 10 years a CBCT study is recommended. It corrects malocclusions and widens the nasopharyngeal area by increasing the volume of the upper airways. Children with OSA show improvements in their apnea-hypopnea index, oxygen saturation, and decreased snoring when undergoing RME.

Conclusion: RME works by opening the MPS, resulting in an increase in the transverse dimension of the maxilla. In addition to correcting malocclusions, it increases the volume of the upper airway and is an effective treatment option in patients with OSA who present craniofacial discrepancies.