Background: Polycystic ovarian syndrome (PCOS) is a common, reproductive endocrinopathy associated with ovarian dysfunction, cardiovascular disorders, obesity, and infertility. Myo-inositol is a novel treatment for women with PCOS that claimed to have improved fertility rate in this population. This systematic review and meta-analysis examined the effect of myo-inositol on pregnancy rate, menstrual cycle, and adverse effects from randomized controlled trials (RCTs). Methods: RCTs that evaluated the efficacy of myo-inositol in improving pregnancy rate and regulation of menstrual cycle in women with PCOS. Electronic databases were searched and studies published up to October 24, 2021 were included in the systematic review and meta-analysis. Study selection and assessment of quality were conducted independently by two review authors. Results: Seven studies with 729 patients treated with myo-inositol and 677 patients treated with placebo and/or metformin were included in the analysis. The research groups did not diverge significantly in terms of basic characteristics, such as age, adnexal or uterine pathology, body mass index, and duration of infertility. In the myo-inositol group, regulation of the normal menstrual cycle is at 20%, significantly higher than the metformin group at 12%, (p<0.001). However, there is no significant difference in the pregnancy rate between myoinositol and placebo (p=0.42) and/or metformin (p=0.17). Conclusion: This systematic review and meta-analysis showed that myo-inositol can be an alternative treatment for PCOS in terms of regulation of menses and may improve the success of spontaneous pregnancies. However, additional randomized, double-blind controlled trials with larger sample sizes, low heterogeneity, and uniform inclusion criteria are recommended to establish the effects of myo-inositol on PCOS treatment and pregnancy rate.