The Przewalski′s horse, also called: Khalkha Mongolian; Polish; or Dzungarian horse, is a rare and endangered subspecies of wild horse (Equus ferus) native to the steppes of central Asia. At one time extinct in the wild (in Mongolia, the last wild Przewalski′s horses had been seen in 1966), it has been reintroduced to its native habitat in Mongolia at the Khustain Nuruu National Park, Takhin Tal Nature Reserve, and Khomiin Tal. The taxonomic position is still debated, and some taxonomists treat Przewalski′s horse as a species, Equus przewalskii.

Wild horses today, such as the American mustang or the Australian brumby, are actually feral horses descended from domesticated animals that escaped and adapted to life in the wild. In contrast, the Przewalski′s horse has never been domesticated and remains the only true wild horse in the world today.

There are still a number of other wild equines, including three species of zebra and various subspecies of the African wild ass, onager (including the Mongolian wild ass), and kiang.

In the wild, Przewalski′s horses live in small, permanent family groups consisting of one adult stallion, one to three mares, and their common offspring.

Offspring stay in the family group until they are no longer dependent, usually at two or three years old.

Bachelor stallions, and sometimes old stallions, join bachelor groups. Family groups can join together to form a herd that moves together.

The native population declined in the 20th century due to a combination of factors, with the wild population in Mongolia dying out in the 1960s. The last herd was sighted in 1967 and the last individual horse in 1969. Expeditions after this failed to locate any horses, and the species had been designated "extinct in the wild" for over 30 years

After 1945 only two captive populations in zoos remained, in Munich and in Prague. The most valuable group, in Askania Nova, Ukraine, was shot by German soldiers during World War II occupation, and the group in the United States had died out. Competition with livestock, hunting, capture of foals for zoological collections, military activities, and harsh winters recorded in 1945, 1948 and 1956 are considered to be the main causes of the decline in the Przewalski′s wild horse population. By the end of the 1950s, only 12 individual Przewalski′s horses were left in the world

Every Przewalski horse presently living is descended from 9 of the 13 horses captured in 1945. Two of these were hybrids, one sired from a wild horse stallion and domestic mare and the other from a wild stallion and a tarpan mare. These 13 horses were descended in turn from approximately 15 captured around 1900.

A cooperative venture between the Zoological Society of London and Mongolian scientists has resulted in successful reintroduction of these horses from zoos into their natural habitat in Mongolia, and as of 2011 there is an estimated free-ranging population of over 300 in the wild.

From a population of 13 horses held in captivity in 1945, the total number by the early 1990′s was over 1,500. A population introduced in 1998 exists in the Chernobyl Exclusion Zone protected from interference by humans, and is thought to be increasing in size.