The knowledge of the normal lung structure is essential for understanding diseases of the lung. The macroscopic structure with lung lobes, fissures, and the pleura as well as microscopic features of the airways and the functional lung parenchyma are equally important. The knowledge about the vascular structures and the lymphatics is presented, and specific cells and their function within bronchi and alveoli are discussed. Structures such as cartilage and nerves and the role of the mesenchyme will be discussed. Finally specific differences in lung structure among different species are discussed.