Dwarf elephants are prehistoric members of the order Proboscidea which, through the process of allopatric speciation on islands, evolved much smaller body sizes (around 1–2.3 metres (3 ft 3 in – 7 ft 7 in) shoulder height) in comparison with their immediate ancestors. Dwarf elephants are an example of insular dwarfism, the phenomenon whereby large terrestrial vertebrates (usually mammals) that colonize islands evolve dwarf forms, a phenomenon attributed to adaptation to resource-poor environments and lack of predation and competition.

Fossil remains of dwarf elephants have been found on the Mediterranean islands of Cyprus, Malta, Crete, Sicily, Sardinia, the Cyclades Islands and the Dodecanese Islands, which are mostly members of the genus Palaeoloxodon, descending from the large 4 metres (13 ft) tall straight-tusked elephant (Palaeoloxodon antiquus) of mainland Europe, though two species represent dwarf mammoths. Dwarf species of elephants and Stegodon have been found on the islands of Indonesia and the Philippines, with dwarfed species of Stegodon also having been found in Japan. The Channel Islands of California once supported the pygmy mammoth, a dwarf species descended from Columbian mammoths, while the woolly mammoths that existed on Wrangel Island north of Siberia were once considered dwarfs, but are not anymore.

Dwarf elephants first inhabited the Mediterranean islands during the Pleistocene, including all the major islands with the apparent exception of Corsica and the Balearics. Mediterranean dwarf elephants have generally been considered as members of the genus Palaeoloxodon, derived from the continental straight-tusked elephant, Palaeoloxodon antiquus (Falconer & Cautley, 1847), Syn.: Elephas antiquus. An exception is the dwarf Middle-Late Pleistocene Sardinian mammoth, Mammuthus lamarmorai (Major, 1883), the first endemic elephant of the Mediterranean islands recognized as belonging to the mammoth line. Mammuthus creticus from the Early Pleistocene of Crete, formerly considered a member of Palaeoloxodon, is now also considered to be a mammoth, and approaches the size of the smallest dwarf elephants.

During low sea levels, the Mediterranean islands were colonised again and again, giving rise, sometimes on the same island, to several species (or subspecies) of different body sizes. The island of Sicily appears to have been colonised by proboscideans in at least two separate waves of colonisation. These endemic dwarf elephants were taxonomically different on each island or group of very close islands, like the Cyclades archipelago.

There are many uncertainties about the time of colonisation, the phylogenetic relationships and the taxonomic status of dwarf elephants on the Mediterranean islands. Extinction of the insular dwarf elephants has not been correlated with the arrival of humans to the islands, with the exception of Palaeoloxodon cypriotes on Cyprus, which survived until human colonisation of the island around 12,000 years ago.

Palaeontologist Othenio Abel proposed in 1914 that the finding of skeletons of such elephants sparked the idea that they belonged to giant one-eyed monsters, because the center nasal opening was thought to be the socket of a single eye, and thus perhaps were, for example, the origin of the one-eyed Cyclopes of Greek mythology. While this claim has been widely been repeated, it has been criticised for lacking evidence.

Sicily and Malta were inhabited by two successive waves of dwarf elephants derived from P. antiquus, which first arrived on the islands at least 500,000 years ago. The first of these species is P. falconeri , which is one of the smallest dwarf elephant species at around 1 metre (3.3 ft) tall, and was strongly modified from its ancestor in numerous aspects, which lived in a depauperate fauna with no other large mammal species. Later, around 200,000 years ago, this species was replaced by a second colonisation by P. antiquus, which gave rise to the larger (though still considerably dwarfed) 2 metres (6.6 ft) tall species P. mnaidriensis, which on Sicily lived alongside a number other large mammal species, including herbivores and carnivores. The youngest records of this species on Sicily date to around 20,000 years ago, close to the time of arrival of modern humans on Sicily.

The dwarf mammoth species Mammuthus lamarmorai descended from steppe mammoths (Mammuthus trogontherii) that colonised Sardinia sometime after 450,000 years ago. It is suggested to have survived into the Last Glacial Period, until at least 60-30,000 years ago.