A horse archer is a cavalryman armed with a bow and able to shoot while riding from horseback. Archery has occasionally been used from the backs of other riding animals. In large open areas, it was a highly successful technique for hunting, for protecting the herds, and for war. It was a defining characteristic of the Eurasian nomads during antiquity and the medieval period, as well as the Iranian peoples such as the Alans, Sarmatians, Cimmerians, Scythians, Massagetae, Parthians, and Persians in Antiquity, and by the Hungarians, Mongols, Chinese, and Turkic peoples during the Middle Ages. The expansion of these cultures have had a great influence on other geographical regions including Eastern Europe, West Asia, and East Asia. In East Asia, horse archery came to be particularly honored in the samurai tradition of Japan, where horse archery is called Yabusame.
The term mounted archer occurs in medieval English sources to describe a soldier who rode to battle but who dismounted to shoot. Horse archer is the term used more specifically to describe a warrior who shoots from the saddle at the gallop. Another term, "horseback archery", has crept into modern use.
Horse archery developed separately among the people of the South American pampas and the North American prairies following the introduction of domesticated horses to the continent; the Comanches were especially skilled.
Since using a bow requires the rider to let go of the reins with both hands, horse archers need superb equestrian skills if they are to shoot on the move. The natives of large grassland areas used horse archery for hunting, for protecting their herds, and for war. Horse archery was for many groups a basic survival skill, and additionally made each able-bodied man, at need, a highly mobile warrior. The buffalo hunts of the North American prairies may be the best-recorded examples of bowhunting by horse archers.
In battle, light horse archers were typically skirmishers, lightly armed missile troops capable of moving swiftly to avoid close combat or to deliver a rapid blow to the flanks or rear of the foe.