Cells which are capable of secreting an enzyme or hormone in a gland form the parenchyma of the gland. Rest of the tissue present in the gland form the supporting tissue of the gland. Parenchymal cells develop from either ectoderm or endoderm. This chapter covers the development of major salivary glands, development of the thyroid gland, and development of pituitary gland. The pituitary gland has two major parts. They are adenohypophysis and neurohypophysis. Both are different from each other by their development, structure and function. The adenohypophysis is derived from stomodeum (surface ectoderm). The neurohypophysis is derived from neural tube from the neuroectoderm.