Social anxiety disorder is a common psychiatric disorder characterized by fear and avoidance of situations associated with scrutiny by others. Its neural basis, particularly with regard to connectivity of the brain's white matter, is largely unknown. The present thesis sought to fill this gap and to contribute to a deeper understanding of the pathophysiology. It strongly suggests that the structural integrity and size of the uncinate fasciculus, a white matter fiber bundle interconnecting frontal and temporal lobes, are compromised in social anxiety disorder. It also points to the fact that the specific structural features of the uncinate fasciculus are linked to the level of anxiousness in non-clinical individuals. Taken together, fronto-temporal structural connectivity in the brain might represent a neural basis of mechanisms linked to the emergence and/or regulation of anxiety that become critically altered in pathological anxiety. For future research in neuropsychiatry, thus, the uncinate fasciculus may serve as important target structure with potential implications for the development and treatment of anxiety disorders.