Obstructive sleep apnea (OSA) is a highly prevalent sleep disorder associated with obesity, hypertension and metabolic syndrome. People with low socioeconomic status (SES) who are socially disadvantaged (eg, people belonging to an ethnic minority) have worse health outcomes. Thus, consequently, social inequality may potentially be a risk factor for OSA. This systematic review aims to summarize previous studies from the literature which investigate the association between SES, race/ethnicity and obstructive sleep apnea (OSA). This review was performed in accordance with the PRISMA statement. A literature search in Medline, PubMed, PsycINFO, Scopus, and Web of Science was conducted. Articles published in English, Spanish, French, Italian and Portuguese, without publication date limits, and that aimed to analyze the association between OSA diagnosis and social disadvantage, were selected. In sum, 17 articles met the inclusion criteria. One was a longitudinal study, and the remainder were cross-sectional research. Low SES was indicated as a risk factor for the presence of OSA in most of the articles. Concerning racial/ethnic groups, a clear association with OSA does not emerge, since, in a few articles, the relation disappeared after controlling for variables such as obesity, comorbidities, and SES; suggesting that there may be differences only in OSA severity and sleep apnea phenotypes. The results of this systematic review point out that low SES could be a risk factor for OSA. Obesity, SES and disparities in health care could mediate the association between OSA and racial/ethnic minorities. Socioeconomic circumstance should receive more attention in sleep medicine research.