Carl Linnaeus first described the genus Elephas and an elephant from Ceylon under the binomial Elephas maximus in 1758. In 1798, Georges Cuvier first described the Indian elephant under the binomial Elephas indicus. In 1847, Coenraad Jacob Temminck first described the Sumatran elephant under the binomial Elephas sumatranus. Frederick Nutter Chasen classified all three as subspecies of the Asian elephant in 1940.
Three subspecies are currently recognised: the Sri Lankan elephant, the Indian elephant, and the Sumatran elephant. In 1950, Paules Edward Pieris Deraniyagala described the Borneo elephant under the trinomial Elephas maximus borneensis, taking as his type an illustration in National Geographic, but not a living elephant in accordance with the rules of the International Code of Zoological Nomenclature. E. m. borneensis lives in northern Borneo and is smaller than all the other subspecies, but with larger ears, a longer tail, and straight tusks. Results of genetic analysis indicate that its ancestors separated from the mainland population about 300,000 years ago.
The population in Vietnam and Laos was tested to determine if it is a subspecies as well. This research is considered vital, as less than 1,300 wild Asian elephants remain in Laos. In addition, two extinct subspecies are considered to have existed:
- The Chinese elephant is sometimes separated as E. m. rubridens (pink-tusked elephant); it disappeared after the 14th century BC.
- The Syrian elephant (E. m. asurus), the westernmost and the largest subspecies of the Asian elephant, became extinct around 100 BC. This population, along with the Indian elephant, was considered the best war elephant in antiquity, and was found superior to the smallish North African elephant (Loxodonta africana pharaoensis) used by the armies of Carthage.