The obstructive sleep apnea syndrome (OSAS) is characterized by a reduction or absence of airflow in the oral or nasal cavity. The rapid maxillary expansion device (RME) has been considered an important treatment option. The objective is to review the literature to assess the effectiveness of RME in the treatment of children with OSAS. A research was developed over the following primary and secondary electronic data bases MEDLINE / PubMed, Embase, CINAHL, LILACS, Cochrane and OvidSP. A search strategy was made using the English terms: "Palatal Expansion Technique" [MeSH] AND "Sleep Apnea, Obstructive" [ MeSH] limited to randomized controlled trials, cohort studies, systematic review and meta-analysis, in Portuguese and English, performed in humans under 18 years and regarding articles published between January 1st 2000 and January 2014. In this review, a total of 36 articles were identified, 17 of which were considered potentially relevant. After applying the inclusion and exclusion criteria, 6 publications were accepted. Among these, only 4 had a positive result after the CASP quality assessment and therefore were included in this study. The RME is effective in the treatment of children with OSAS combined with inadequate respiratory capacity and transverse maxillary deficiency, resulting in the improvement of polysomnographic variables, especially in the apnea-hypopnea index. In children with maxillary endognatia presenting no adenotonsillar hypertrophy, as well as no neuromuscular disorders, cardiorespiratory or craniofacial anomalies, RME is a valid option for treating OSA. Keywords: Systematic Review, Obstructive sleep apnea syndrome, rapid maxillary expansion, Mouth Breather, apnea-hypopnea index, adeno-tonsillectomy