This systematic review was carried out to determine if maxillomandibular fixation, used in the treatment of maxillary fractures, interferes with respiratory function, and appraised studies that evaluated pulmonary function using spirometry on patients with and without maxillomandibular fixation. Searches were conducted on the following databases: Medline/Pubmed, Embase, Cochrane, Web of Science, Scopus, and Scielo, in addition to a search of the grey literature and a manual search. Five studies were included in the qualitative analysis, but it was not possible to conduct a quantitative study due to the lack of data. Forced vital capacity, forced expiratory volume in the first second, the ratio of these values, and peak expiratory flow were the parameters studied. In all the studies included in this review, it was possible to observe the lowest respiratory parameter values during maxillomandibular fixation and, after removal, normal respiratory function was restored. Accordingly, it was possible to conclude that maxillo-mandibular fixation temporarily affects respiratory function, during use, but it is restored on removal, therefore, not precluding its use on healthy patients who have good nasal breathing prior to the procedure. However, in patients suffering from some form of respiratory limitation or pulmonary disease, and also mouth breathers, maxillomandibular fixation should not be used so as to avoid more severe respiratory complications, underlining the importance of preoperative pulmonary evaluation.