Nativism is the political policy of promoting or protecting the interests of native-born or indigenous people over those of immigrants, including the support of anti-immigration and immigration-restriction measures.

According to Cas Mudde, a University of Georgia professor, nativism is a largely American notion that is rarely debated in Western Europe or Canada; the word originated with mid-19th-century political parties in the United States, most notably the Know Nothing party, which saw Catholic immigration from nations such as Germany and Ireland as a serious threat to native-born Protestant Americans. In the United States, nativism does not refer to a movement led by Native Americans, also referred to as American Indians.

According to Joel S. Fetzer, opposition to immigration commonly arises in many countries because of issues of national, cultural, and religious identity. The phenomenon has especially been studied in Australia, Canada, New Zealand, the United Kingdom, and the United States, as well as in continental Europe. Thus, nativism has become a general term for opposition to immigration which is based on fears that immigrants will "distort or spoil" existing cultural values. In situations where immigrants greatly outnumber the original inhabitants, nativists seek to prevent cultural change.

Beliefs that contribute to anti-immigration sentiment include:

Hans-Georg Betz examines three facets of nativism: economic, welfare, and symbolic. Economic nativism preaches that good jobs ought to be reserved for native citizens. Welfare nativism insists that native citizens should have absolute priority in access to governmental benefits. Symbolic nativism calls on the society and government to defend and promote the nation's cultural heritage. Betz argues that economic and welfare themes were historically dominant, but that since the 1990s symbolic nativism has become the focus of radical right-wing populist mobilization.

Many Australians opposed the influx of Chinese immigrants at time of the nineteenth-century gold rushes. When the separate Australian colonies formed the Commonwealth of Australia in 1901, the new nation adopted "White Australia" as one of its founding principles. Under the White Australia policy, entry of Chinese and other Asians remained controversial until well after World War II, although the country remained home to many long-established Chinese families dating from before the adoption of White Australia. By contrast, most Pacific Islanders were deported soon after the policy was adopted, while the remainder were forced out of the canefields where they had worked for decades.

Antipathy of native-born white Australians toward British and Irish immigrants in the late 19th century was manifested in a new party, the Australian Natives' Association.

Since early 2000, opposition has mounted to asylum seekers arriving in boats from Indonesia.