This article summarizes the main pathophysiological mechanisms that link chronic obstructive pulmonary diseases, especially COPD and emphysema, to the development of pulmonary hypertension (PH). Unlike bronchial asthma, COPD and emphysema are characterized by irreversible obstruction, mainly associated with structural changes in the bronchial wall and destruction of the alveolar architecture, mainly caused by smoking. In COPD, mucus hyperproduction, hypertrophy of mucous glands, and decreased mucociliary clearance follow persistent airway narrowing, while in emphysema, damage to elastic fibers due to protease–antiprotease imbalance predominates, resulting in bronchiolar collapse and “air trapping”.