Symptomatic calcium disorders—most notably, hypocalcemia— are common problems in preterm and certain term infants. Many factors predispose susceptible neonates to hypo- or hypercalcemia, but in many cases, the root of the problem is altered function of the parathyroid glands. Parathyroid gland dysfunction may affect calcium homeostasis and alter physiologic functioning, resulting in significant clinical symptoms. A review of how the parathyroid glands and parathyroid hormone affect calcium balance and of the problems that result from altered function promotes a better appreciation of the important role played by these sometimes “forgotten” glands in maintaining normal neonatal physiologic functioning.