Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women associated with cardiovascular disease and obesity. The possible benefits of omega-3 supplementation in this syndrome have been discussed much. This study is aimed to verify, based on the scientific data published, if there are any benefits in the omega-3 supplementation in the treatment of PCOS and to indicate its possible dosages for the treatment of polycystic ovary. The work consists of a systematic review of clinical trials and cohort of the MEDLINE/PubMed database from 2009 to October 2019. All studies that analyzed the omega-3 supplementation in women with PCOS were included. Cross-sectional studies, review articles, systematic reviews, meta-analysis, duplicates, studies in animals or cell culture, studies with omega-3 supplementation via food or associated with other supplementations were not included, except those involving vitamin E. In total, 21 articles were selected. Despite the heterogeneity of the studies selected, indirect benefits were observed mainly regarding the glycemic profile, such as insulin resistance reduction, lipid profile modulation (i.e. decrease in total cholesterol, triglycerides, and elevation of high-density lipoprotein), and the regulation of the androgenic profile. As for the anthropometric profile, the studies were scarce and most of them had no significant meaning. Regarding the antioxidant profile and inflammatory biomarkers, the findings differ among studies, but promising results were observed with different doses over 12 weeks of use, such as C-reactive protein (CRP) reduction. Thus, omega-3 fatty acids promote indirect benefits in the treating of women with PCOS. However, to reveal well-defined standards for dosage and supplementation time, further studies are needed.