Airway diseases, affecting various levels of the tracheobronchial tree, are globally prevalent. Imaging plays a crucial role alongside clinical and laboratory tests in diagnosing, characterising and managing these conditions. Cross-sectional imaging holds promise for improving our understanding of disease mechanisms, progression and treatment response. Quantitative imaging, which involves extracting measurable data from CT predominantly, enhances diagnostic accuracy and reduces observer variability. It enables early detection of disease—such as mild emphysema visible on HRCT before spirometry can detect it—allowing for timely intervention, especially in younger patients. As computing power grows, automated quantitative imaging will improve efficiency and clinical workflow. This chapter reviews common airway diseases like COPD, asthma, and bronchiectasis, along with rarer conditions, and explores quantitative imaging techniques according to the anatomical location of abnormalities.