Tendons connect animal skeletons to skeletal muscles, playing a crucial role in weight-bearing and maintaining motor functions. After decellularization, tendon extracellular matrix (tECM) retains the physicochemical characteristics similar to those of native tendons. This has made tECM a promising biomaterial in the fields of tissue engineering and regenerative medicine in recent years. This paper summarizes the origin, structure, and ECM components of animal tendons, reviews decellularization methods, and discusses recent advancements in the research and applications of decellularized tendons. Furthermore, it explores future development trends of xenogeneic decellularized tendon materials, aiming to provide a reference for fundamental research and the development of biomaterials related to decellularized tendons.