© 2015 by the Endocrine Society. The prevalence of vitamin D deficiency in pregnancy is increasing and implicated in adverse consequences for the health of offspring in later life. The aim of this study was to determine whether vitamin D deficiency increases fetal exposure to glucocorticoids, which are known to alter fetal development and result in adverse adult health outcomes. Female BALB/c mice were placed on either a vitamin D control (2195 IU/kg) or deficient (0 IU/kg) diet for 5 weeks before and during pregnancy. Maternal serum, placentasandfetal brainswerecollected at embryonic day 14.5 or 17.5 for morphological and gene expression analysis. Vitamin D deficiency during pregnancy increased maternal corticosterone concentrations and reduced placental weight. Maternal vitamin D deficiency decreased placental expression of 11-hydroxysteroid dehydrogenase type II, which inactivates glucocorticoids thereby protecting the fetus from inappropriate glucocorticoid exposure. There was a corresponding increase in placental and fetal expression of the highly glucocorticoidsensitive factor glucocorticoid-induced leucine zipper. Furthermore, placental expression of the angiogenic factor vascular endothelial growth factor-A was reduced in vitamin D-deficient pregnancies, with a corresponding decline in fetal capillary volume within the placenta. Overall, we show that prenatal vitaminDdeficiency leads to an increase in maternal corticosterone, alterations in genes indicative of increased fetal glucocorticoid exposure and impairment in placental vascular development. Thus, the long-term adverse health consequences of vitamin D deficiency during early development may not just be due to alteration in direct vitamin D-related pathways but also altered fetal glucocorticoid exposure.