Allografts have an essential significance in the surgical reconstruction of ligamentous injuries around the knee joint. While in primary anterior cruciate ligament reconstruction allografts are less important than autografts, at least in the European countries, the usage of allografts in anterior cruciate ligament revision surgery is increasing. In addition, allografts represent a good alternative for the reconstruction of the posterior cruciate ligament and the posterolateral structures. Especially in multiligament reconstructions of the knee joint, the usage of allografts may prevent iatrogenic damage of the already traumatized periarticular soft tissue. The present article focuses on the application and clinical results of allografts for ligament reconstruction around the knee joint. Furthermore, the immunological and biological principles of tendon allografts, their availability, processing, and security are discussed.