Introduction: Polycystic ovary syndrome (PCOS) is a common hormonal and metabolic condition affecting women of reproductive age. It is characterized by persistent anovulation, increased androgen levels, insulin resistance, and mild inflammation. Women with PCOS are more susceptible to cardiovascular and metabolic complications. The present study was aim to investigate the correlation between body mass index and serum vitamin D levels in women with PCOS. Methods: The present study was designed as cross sectional comparative study. The volunteers were recruited from the gynecology department of a tertiary care hospital and studied in the department of Physiology. The present study included 120 women between 18- 40 years. The study participants were divided into 2 groups. Group N included 52 volunteers with normal levels of vitamin D in women with PCOS and Group D includes 68 volunteers with hypovitaminosis D in women with PCOS. Results: The study involved 120 patients with PCOS, categorized into two groups, N and D. In Group N, 15.38% (n = 8) were underweight, 61.53% (n = 32) had normal weight, 17.31% (n = 9) were overweight, and 5.77% (n = 3) were obese. In Group D, 10.29% (n = 7) were underweight, 27.94% (n = 19) had normal weight, 39.71% (n = 27) were overweight, and 22.06% (n = 15) were obese. The analysis of BMI showed significant differences in the rates of overweight and obesity between Groups N and D (p = 0.008 and 0.013, respectively). Furthermore, a negative correlation was observed between BMI and serum vitamin D levels across all participants.