Diseases of the anterior cruciate ligaments represent one of the most common orthopedic pathologies in dogs, causing significant pain and instability in the stifle joint, which leads to the development of osteoarthritis. Rupture of the anterior cruciate ligament disrupts the biomechanical balance of the joint, and factors such as breed, age, sex, and body weight increase the risk of injury. Mechanical stress caused by the slope of the tibial plateau and other biomechanical forces also contribute to ligament weakening. Degenerative changes within the ligaments are considered the primary cause of rupture, while genetics plays a significant role; however, its true impact has not yet been fully clarified. In addition to biomechanical aspects, immunopathological mechanisms are increasingly being investigated, with evidence showing that cruciate ligaments can become autoantigens after injury, triggering a local immune response and chronic inflammation. Cytokines, proteolytic enzymes, and the infrapatellar fat pad play key roles in these processes, and an imbalance between pro-inflammatory and antiinflammatory factors can lead to progressive degeneration of joint tissue and further complications. Postoperative rehabilitation and appropriate treatment are of utmost importance for restoring joint functionality and preventing further degeneration. Although significant progress has been made in understanding this pathology, further research is needed to clarify the exact immunopathological mechanisms, genetic factors, and the role of the infrapatellar fat pad, as well as to develop new treatment and prevention strategies for these diseases in dogs.