Sinomastodon ("Chinese mastodont") is an extinct gomphothere genus (of order Proboscidea), from the Late Miocene to the Early Pleistocene deposits of south-east Asia (China, Japan, and Indonesia). It is not to be confused with the genus Mammut from a different proboscidean family, whose members are commonly called "mastodons".The animal was very similar to modern elephants with size ranging from 3.6 to 5.3 m. Several species are known from China, the best known being S.