Aim: This study aimed to evaluate the morphological changes in the diameter and length of the trachea, bronchi, and pulmonary artery on chest CT images of COVID-19 patients, and to compare the findings with those of a healthy control group. In addition, the obtained data were analyzed across patient groups classified as mild, moderate, and severe according to the degree of pulmonary involvement. Methods: In this study, thoracic CT images of 78 patients who were diagnosed with and treated for COVID-19 and 52 healthy controls were retrospectively analyzed. Diameter and length measurements of the trachea and bronchi, as well as the diameter of the pulmonary artery, were obtained. Based on the extent of pulmonary involvement observed on CT, the patients were divided into three groups: mild, moderate, and severe. The measurements obtained were compared with those of a control group matched for age and sex. Results: In COVID-19 patients, compared to the control group, a marked decrease in tracheal and bronchial diameters was detected according to sex and CT involvement level, while an increase in pulmonary artery diameter was observed. The severity of these changes was found to increase in parallel with the extent of lung involvement. Conclusions: COVID-19 infection causes measurable morphological changes in the airways and vascular structures. We believe that the combined evaluation of lung CT findings and pulmonary artery diameter may guide future studies based on morphometric measurements in revealing the relationship with mortality and morbidity. We believe that the findings of our study will contribute to the existing literature on COVID-19.