The Kiger mustang is a strain of mustang horse located in the southeastern part of the U.S. state of Oregon. The name applies only to wild-captured individuals and does not apply to their bred-in-captivity progeny, which are known as Kiger horses. The Bureau of Land Management (BLM) administers two herd management areas for Kiger mustangs in the Burns District—Kiger and Riddle Mountain, in the Steens Mountain area. DNA testing has shown that Kiger mustangs are descended largely from Spanish horses brought to North America in the 17th century, a bloodline thought to have largely disappeared from mustang herds before the Kiger horse populations were discovered in 1977.

The mustang is a free-roaming horse of the Western United States, descended from horses brought to the Americas by the Spanish conquistadors. Mustangs are often referred to as wild horses, but because they are descended from once-domesticated animals, they are actually feral horses. The original mustangs were Colonial Spanish horses, but many other breeds and types of horses contributed to the modern mustang, now resulting in varying phenotypes. Some free-roaming horses are relatively unchanged from the original Spanish stock, most strongly represented in the most isolated populations.