Thoracic vascular malformations are a set of complex congenital abnormalities that result in major alterations of the patient's anatomy. It can be discovered incidentally or the anomalies may generate heart failure with a right-to-left shunt, dysphagia, dyspnea, stridor, cough, recurrent bronchopulmonary infections, hypoxemia, paradoxical emboli, and occasionally apneas and massive hemothorax.The knowledge of the embryology, and the normal development of the vascular structures of the thorax, allows to understand these abnormalities—and thus helps in making an accurate diagnosis—with its possible complications, symptoms, and treatments for the patient. The following is a review of the most common thoracic vascular malformations and their imaging findings.