Canine appendicular osteosarcoma (OSA) is the most common primary malignant bone tumor in dogs and is characterized by aggressive local growth and early metastatic spread. Prognosis remains poor, largely due to the presence of micrometastatic disease at the time of diagnosis. This review summarizes current knowledge on the epidemiology, diagnostic approaches, and treatment strategies for canine appendicular osteosarcoma. A literature review was conducted using PubMed, Scopus, and Google Scholar, focusing on studies published between 2000 and 2025, with an emphasis on the most recent findings. Amputation with adjuvant chemotherapy is still the best way to treat cancer, and it does improve survival, but it doesn't stop the cancer from spreading. Limb-sparing surgery and stereotactic body radiation therapy (SBRT) may be considered in selected cases to preserve limb function, but they do not appear to offer a survival advantage compared to amputation. Palliative treatments, including radiotherapy and analgesic management, play an important role in maintaining quality of life. Novel approaches such as immunotherapy and targeted therapy have shown promising early results. However, these approaches are largely still in the research phase. Overall, canine appendicular osteosarcoma should be considered a systemic disease. Better control of metastatic disease in the future will improve outcomes through the integration of novel systemic therapies‎‎‎.