"Thoracic outlet syndrome" is a term that covers a range of conditions and abnormalities causing a variety of presentations and symptoms. In order to assess and treat this group of conditions, careful consideration needs to be given to individual presentations to tailor appropriate clinical and imaging tests. There is no single test available for the definitive diagnosis and assessment of this group of conditions. This article aims to present an up-to-date review with particular focus on the diagnosis and relevance of the different imaging modalities. Chest radiography allows identification of bony abnormalities and apical lung tumors. Ultrasonography is useful in cases of suspected acute thrombosis of the upper limb. Computed tomography combined with computed tomography angiography provides a useful overview of the anatomical and vascular structures. Magnetic resonance imaging and magnetic resonance angiography are now widely used methods of assessment for vascular thoracic outlet syndrome, allowing dynamic assessment of the thoracic outlet, with good soft tissue contrast allowing for visualization of a wider range of pathologies than other imaging methods.