The pulmonary vascular pathology in chronic lung diseases, such as chronic obstructive pulmonary disease and interstitial lung diseases, is significantly influenced by the biology of the extracellular matrix (ECM). This chapter explores the fundamental role of ECM in the vascular remodeling processes that can lead to pulmonary hypertension. Alterations of ECM components, including collagens, elastin, and glycoproteins, changes in their post-translational modification, and their fragments contribute to vascular remodeling. This chapter aims to offer a comprehensive overview of the ECM’s involvement in pulmonary vascular pathology, highlighting current research advancements and proposing future directions for clinical application and research endeavors.