Studies in mammals have shown that the fetus maintains a plasma calcium concentration that is higher than that of the mother. This high fetal calcium level is essential for the proper development and mineralization of the fetal skeleton, and the fetal parathyroid glands play an important role in this process. Hormones elaborated by the fetal parathyroid gland, including parathyroid hormone-related protein, are required to maintain the fetal calcium gradient created through active placental transport of calcium by syncytiotrophoblast [1]. This chapter focuses on the histological features of the fetal parathyroid glands.