A 9-year-old female Saanen goat died following swelling of the right cheek and loss of appetite. Necropsy revealed a subcutaneous mass on the right cheek measuring 7 × 5 × 5 cm and another mass on the dorsal soft palate measuring 5 × 5 × 5 cm. Neither mass was continuous with the maxillary bone. Histopathological examination showed that both masses were predominantly composed of atypical spindle-shaped cells. Osteoclast-like multinucleated giant cells were frequently observed, along with scattered osteoid formation and calcified osteoid tissue. Immunohistochemical analysis revealed that the tumor cells were positive for vimentin but negative for keratin. Based on these findings, the mass was diagnosed as a giant cell-rich extraskeletal osteosarcoma, representing only the first such case reported in a goat.