Introduction: Vitamin D Deficiency (VDD) is a global problem among pregnant women in many populations. There is an association between VDD and some pregnancy outcomes, as well as gestational diabetes mellitus (GDM) and pre-eclampsia. We aimed to evaluate the effect of vitamin D supplementation on metabolic status (Fasting Blood Sugar (FBS), insulin, Homeostasis model of assessment-insulin resistance (HOMA-IR) and lipid profile) and blood pressure (BP) among pregnant women with VDD. Methods: A clinical trial was carried out on 30 pregnant women with VDD referring to the Gynecology & Obstetrics Clinic of Baqiyatallah Hospital, Tehran, Iran. The present study had two phases of vitamin D3 supplementation (50000 IU / week for 12 weeks and then 50000 IU / month for three months). Serum total cholesterol, triglyceride, Low Density Lipoprotein (LDL), High Density Lipoprotein (HDL), 25-hydroxyvitamin D (25(OH) D) level, insulin, Fasting Blood Sugar (FBS) and both systolic and diastolic blood pressure were measured. Homeostasis model of assessment-insulin resistance (HOMA-IR) was also determined. Results: The results showed that mean levels of Insulin (p=0.010), HOMA-IR (p=0.020), 25(OH) D level (p=0.001), cholesterol (p=0.001), triglyceride (p=0.001) and LDL (p=0.001) significantly increases during study period. However, Diastolic and systolic blood pressure, FBS, and HDL levels did not change significantly over time. Conclusion: The results of this investigation showed that weekly and monthly vitamin D3 supplementation in pregnant women with VDD had beneficial effects on glycemic status, lipid profile and blood pressure.