Introduction: The treatment of male sexual disorders, considering the side effects of chemical drugs, it is more desirable to identify appropriate approaches such as herbal medicines with fewer side effects. The aim of this study was to explain the role of onion (Allium cepa) as a complementary treatment in improving male sexual disorders. Method: This review identified the existing studies from the beginning to 2023 related to the purpose of the article in PubMed, Web of Science, Scopus, Embase, and Google Scholar databases with keywords “Allium cepa, Onion, Male sexual dysfunction, Erectile disorder, Libido, Men's sexual health, and Testosterone”. Results: Totally, 17 articles related to the research topic were included in the final review. Onion products (including juice, aqueous extract, skin, ethyl acetate fraction, and seed extract) were used, mostly orally consumed over a period of 10-60 days. Conclusion: Onion through increasing testosterone (with the mechanisms of increasing LH production, antioxidant properties, improving insulin resistance, increasing nitric oxide production, and changing the activity of AMP 5-activated protein kinase) as well as treating erectile dysfunction and on the other hand improving reproductive status with positive effects on sperm (number, survival and motility) and its effects against infectious agents may have positive effects on male reproductive system. Although, there is a lot of evidence that onions can improve male sexual disorders, clinical trials are necessary to confirm this effect of onion in humans.