Polycystic ovary syndrome (PCOS) is a complex disorder commonly affecting women of reproductive age. Diagnostic criteria include abnormal menstrual cycles, elevated androgens, and cystic ovaries, although insulin resistance is also common. PCOS puts patients at an elevated risk for complications such as type 2 diabetes and cardiovascular disease, so proper management of this condition is essential. It has been found that vitamin D deficiency is prevalent among the PCOS patient population, therefore, this study aims to evaluate the efficacy of vitamin D supplementation as a treatment for PCOS. A meta-analysis was performed using six randomized, placebo-controlled trials that each examined the effects of vitamin D administration in PCOS women compared to a control group. Subgroups of low doses (50,000 IU of vitamin D every 14 – 21 days) and high doses (50,000 IU of vitamin D every 7 days) were employed when possible. Analysis revealed that vitamin D significantly improved fasting plasma glucose and insulin resistance (HOMA-IR) when given in a low dose. Vitamin D also significantly improved insulin levels overall, although the low dose proved more effective. Insignificant yet marginal improvements were observed in total testosterone and insulin sensitivity (QUICKI). These results indicate that vitamin D can benefit some of the metabolic and endocrine parameters that are typically abnormal in PCOS. On this basis, health care providers are urged to test the vitamin D levels of their patients and encourage supplementation when deficiencies are present, as vitamin D may provide a low cost, low risk treatment to patients.