Introduction: PCOS is one of the most common endocrine disorders in women during the reproductive ages and is associated with disturbances of sex-steroid hormones. In this narrative review, we aimed to explore the possible pathways that may explain the association between migraine headaches and PCOS. Methodsand Materials: In this review, PubMed, Scopus, Web of Science and Google Scholar were searched from June 2000 to January 2021) based on subject headings using keywords, polycystic ovary syndrome, PCOS, metabolic syndrome, obesity, sex hormones, androgens, estrogens, progesterone, hypothalamic-pituitary-gonadal axis, insulin resistance, serotonin, migraines, headache, amenorrhea, oral contraception pills (OCPs). Out of 1035 selected articles, there were 102 articles that best matched the present study. Results: Despite the protective effect of hyperanrogenemia on migraine headaches, other manifestations/complications of PCOS may exacerbate the hormonal imbalance and induce migraine headaches. It seems that serotonin is an interface ring between PCOS and migraine headaches through several pathways. On the one hand, the synthesis and absorption of serotonin are affected by estrogens. On the other hand, serotonin which plays a role in modulating the pain threshold takes a downward trend in people with migraines and PCOS. Moreover, serotonin may play a role in down regulation of insulin sensitivity, leading to insulin resistance which occurs in the majority of obese PCOS women. Additionally, oral contraceptive pills as the first treatment choice in women with PCOS may also have adverse effects on migraine headaches by affecting serum serotonin levels. Conclusion: The association between PCOS and migraine headache may be partly explained by reducing serotonin levels, a hypothesis that needs to be investigated in further studies. Research in this area is not enough, and other pathways besides the serotonin pathway should also be considered in this regard.