Plains indigenous peoples (), previously called plain aborigines, are Taiwanese indigenous peoples originally residing in lowland regions, as opposed to Highland indigenous peoples. Plains indigenous peoples consist of anywhere from eight to twelve individual groups, or tribes, rather than being a single ethnic group. They are part of the Austronesian family. Beginning in the 17th century, plains indigenous peoples have been heavily influenced by external forces from Dutch, Spanish, and Han Chinese immigration to Taiwan. This ethnic group has since been extensively assimilated with Han Chinese language and culture; they have lost their cultural identity, and it is almost impossible without careful inspection to distinguish plains indigenous peoples from Taiwanese Han people.
Plains indigenous peoples are recognized by the Taiwan government as "Pingpu Indigenous People". However, only the Kavalan sub-group has been given full rights and privileges. It was not until the mid-1980s that Plains indigenous peoples started gaining interest from historians and anthropologists, leading to increased public attention to this group. These indigenous groups are currently continuing to fight for their identity, rights, and recognition as Taiwanese indigenous peoples. In 2016, the Tsai Ing-wen administration promised to grant official recognition to the Plains indigenous peoples, and a draft bill is being reviewed by the Legislative Yuan as of June 2018.
In The Island of Formosa (1903), former US Consul to Formosa James W. Davidson presented the first English-language account of the indigenous peoples of the whole island, which was almost entirely based on the comprehensive work collected over several years of study by Ino Kanori, the foremost authority on the topic at the time. In Ino's eight-group classification, the Pepo, Puyuma, and Amis groups were known as "domesticated savages", primarily due to their abandonment of ancient customs. Of these three groups, only the Pepo lived in the western plains, where they remained to compete with the Chinese settlers (the Puyuma and Amis inhabited the eastern plains).