In law, an alien is any person (including an organization) who is not a citizen or a national of a specific country,[1][2][3][4] although definitions and terminology differ to some degree depending upon the continent or region. More generally, however, the term "alien" is perceived as synonymous with foreign national.[5]


The term "alien" is derived from the Latin alienus. The Latin later came to mean a stranger, a foreigner, or someone not related by blood.[6] Similar terms to "alien" in this context include foreigner and lander.[7]


"Resident alien" redirects here. For the Syfy show, see Resident Alien (TV series).

Different countries around the world use varying terms for aliens. The following are several types of aliens:

Common law jurisdictions

See also: History of British nationality law § Early English and British nationality law

An "alien" in English law denoted any person born outside of the monarch's dominions and who did not owe allegiance to the monarch. Aliens were not allowed to own land and were subject to different taxes to subjects.[16] This idea was passed on in the Commonwealth to other common law jurisdictions.


In Australia, citizenship is defined in the Australian nationality law. Non-citizens in Australia are permanent residents, temporary residents, or illegal residents (technically called "unlawful non-citizens").[17] Most non-citizens (including those who lack citizenship documents) traveling to Australia must obtain a visa prior to travel. The only exceptions to the rule are holders of New Zealand passports and citizenship, who may apply for a visa on arrival according to the Trans-Tasman Travel Arrangement.[18]

In 2020, in Love v Commonwealth, the High Court of Australia ruled that Aboriginal Australians (as defined in Mabo v Queensland (No 2)) cannot be considered aliens under the Constitution of Australia, regardless of whether they were born in Australia or hold Australian citizenship.[19][20][21]


In Canada, the term "alien" is not used in federal statutes. Instead, the term "foreign national" serves as its equivalent and is found in legal documents. The Immigration and Refugee Protection Act defines "foreign national" as "a person who is not a Canadian citizen or a permanent resident, and includes a stateless person."[22]

United Kingdom

Further information: British Nationality Act

In the United Kingdom, the British Nationality Act of 1981 defines an alien as a person who is not a British citizen, a citizen of Ireland, a Commonwealth citizen, or a British protected person.[23] The Aliens Act of 1905, the British Nationality and Status of Aliens Act of 1914 and the Aliens Restriction (Amendment) Act of 1919 were all products of the turbulence in the early part of the 20th century.

United States

Further information: Refugee Act and United States person

World War II poster

Under the Immigration and Nationality Act (INA) of the United States, "[t]he term 'alien' means any person not a citizen or national of the United States."[2][4] People born in American Samoa or on Swains Island are statutorily "non-citizen nationals."[24] Others, such as natives of Palau and the Marshall Islands, are legal immigrants and aliens for INA purposes.[25]

Every refugee that is admitted to the United States under 8 U.S.C. § 1157 automatically becomes an "immigrant" and then a "special immigrant" after receiving a green card.[10]

People of various background became naturalized at Kennedy Space Center in Florida (2010). Before the naturalization they were lawfully admitted permanent resident aliens.

The usage of the term "alien" dates back to 1798, when it was used in the Alien and Sedition Acts.[26] Although the INA provides no overarching explicit definition of the term "illegal alien", it is mentioned in a number of provisions under title 8 of the US code.[27] Several provisions even mention the term "unauthorized alien".[28] According to PolitiFact, the term "illegal alien" occurs in federal law, but does so scarcely, writing that, "where the term does appear, it's undefined or part of an introductory title or limited to apply to certain individuals convicted of felonies.”[29]

Since the U.S. law says that a corporation is a person,[4] the term alien is not limited to natural humans because what are colloquially called foreign corporations are technically called alien corporations. Because corporations are creations of local state law, a foreign corporation is an out-of-state corporation.

There are a multitude of unique and highly complex U.S. domestic tax laws and regulations affecting the U.S. tax residency of foreign nationals, both nonresident aliens and resident aliens, in addition to income tax and social security tax treaties and totalization agreements.[30]

"Alienage", i.e., citizenship status, has been prohibited since 1989 in New York City from being considered for employment, under that town's Human Rights legislation.[31][32]

Other jurisdictions

Arab states

See also: Bedoon

In the Gulf Cooperation Council (United Arab Emirates, Saudi Arabia, Kuwait, Oman, Bahrain, and Qatar), many non-natives have lived in the region since birth. However, these Arab states do not easily grant citizenship to non-natives.[33][34][35] Most stateless Bedoon in Kuwait belong to indigenous northern tribes.[36]

See also

Notes and references

  1. ^ "Alien". Britannica. Retrieved February 12, 2021. Alien, in national and international law, a foreign-born resident who is not a citizen by virtue of parentage or naturalization and who is still a citizen or subject of another country.
  2. ^ a b Garner, Bryan A. (June 25, 2009). alien (9th ed.). Black's Law Dictionary. p. 84. ISBN 978-0-314-19949-2. Retrieved August 17, 2018. A person who resides within the borders of a country but is not a citizen or subject of that country; a person not owing allegiance to a particular nation. - In the United States, an alien is a person who was born outside the jurisdiction of the United States, who is subject to some foreign government, and who has not been naturalized under U.S. law.
  3. ^ "alien". Retrieved August 17, 2018.
  4. ^ a b c 8 U.S.C. § 1101(b)(3) ("The term 'person' means an individual or an organization.")
  5. ^ 52 U.S.C. § 30121(b) (explaining that "the term 'foreign national' means.... (2) an individual who is not a citizen of the United States or a national of the United States (as defined in section 1101(a)(22) of title 8) and who is not lawfully admitted for permanent residence, as defined by section 1101(a)(20) of title 8.").
  6. ^ Oxford Latin Dictionary entry for Alienus
  7. ^ Van Houtum, Henk. "The mask of the border." The Routledge Research Companion to Border Studies. Routledge, 2016. 71-84.
  8. ^ 8 U.S.C. § 1481 ("Loss of nationality by native-born or naturalized citizen; voluntary action; burden of proof; presumptions")
  9. ^ "Conditional Permanent Residence". United States Citizenship and Immigration Services. October 23, 2020. Retrieved February 10, 2021.
  10. ^ a b Rosenberg, Michael; Rich, Mark D. (April 1995). "Foreign Investment In U.S. Real Estate-Beyond FIRPTA: Regulatory Requirements and Planning StrategiesRequirements and Planning Strategies". University of Miami Business Law Review Unive. 5 (1): 107.
  11. ^ Hennig, Cherie J.; Wang, Ningkun; Yuan, Xiaoli (2006). "Cross‐Border Taxation of Employee Stock Options". The ATA Journal of Legal Tax Research. 4 (1): 59–75. doi:10.2308/jltr.2006.4.1.59.
  12. ^ Shuntich, Louis S. (July 2012). "Estate Planning Strategies for Resident and Nonresident Aliens". Journal of Financial Service Professionals. 66 (4): 55–60.
  13. ^ "alien enemy". Retrieved February 12, 2021.
  14. ^ 8 U.S.C. § 1442 ("Alien enemies"); 18 U.S.C. § 757 ("Prisoners of war or enemy aliens")
  15. ^ Kelly, Charles B. (December 1977). "Counting the Uncountable: Estimates of Undocumented Aliens in the United States". Population and Development Review. 3 (4): 473–481. doi:10.2307/1971686. JSTOR 1971686.
  16. ^ William Blackstone, Commentaries on the Laws of England (1753), Book 1, Chapter 10
  17. ^ Key Issue 5. Citizenship Fact Sheet 5.2 Citizenship in Australia Archived March 12, 2020, at the Wayback Machine Retrieved 2012-03-05.
  18. ^ "Australia's Visitor and Temporary Entry Provisions" (PDF). Joint Standing Committee on Migration, Parliament of Australia. September 27, 1999. Archived from the original (PDF) on June 29, 2011. Retrieved July 20, 2011.
  19. ^ "High Court rules Aboriginal Australians cannot be 'aliens' under the constitution". SBS News. February 11, 2020.
  20. ^ Karp, Paul (February 11, 2020). "High court rules Aboriginal Australians are not 'aliens' under the constitution and cannot be deported". The Guardian. Retrieved February 11, 2020.
  21. ^ Byrne, Elizabeth; Robertson, Josh (February 11, 2020). "Man released from detention as High Court rules Aboriginal people cannot be deported". ABC News. Australian Broadcasting Corporation. Retrieved February 11, 2020.
  22. ^ Immigration and Refugee Protection Act (S.C. 2001, c. 27)
  23. ^ section 51, British Nationality Act 1981
  24. ^ "Tuaua v. United States, 788 F.3d 300". D.C. Circuit. Harvard Law School. June 5, 2015. p. 302.
  25. ^ McElfish, Pearl Anna; Hallgren, Emily; Yamada, Seiji (April 2015). "Effect of US Health Policies on Health Care Access for Marshallese Migrants". American Journal of Public Health. 105 (4): 637–643. doi:10.2105/AJPH.2014.302452. PMC 4358182. PMID 25713965.
  26. ^ "Alien and Sedition Acts". Retrieved November 23, 2011.
  27. ^ See, e.g., 8 U.S.C. § 1252c(a)(1); 8 U.S.C. § 1330(b)(3)(A)(iii); 8 U.S.C. § 1356(r)(3)(ii); 8 U.S.C. § 1365(b) ("An illegal alien ... is any alien ... who is in the United States unlawfully...."); 8 U.S.C. § 1366
  28. ^ 8 U.S.C. § 1324a(h)(3)
  29. ^ Selby, W. Gardner (May 9, 2018). "Is 'illegal alien' a term in federal law?". PolitiFact. Retrieved February 26, 2019.
  30. ^ "Foreign Nationals: Non-Resident Aliens and Resident Aliens". Protax Consulting Services.
  31. ^ Tyler Blint-Welsh (September 25, 2019). "New York City Employers Who Say 'Go Back to Your Country' Could Face Fines". The Wall Street Journal. Retrieved September 30, 2019. Since 1989, the city's human-rights law has banned discrimination based on citizenship status or "alienage" in employment, housing and public accommodations.
  32. ^ "The protected classes covered under the New York City Human Rights Law are:Age Alienage or Citizenship Status"
  33. ^ Habboush, Mahmoud (October 10, 2013). "Call to naturalise some expats stirs anxiety in the UAE". Reuters.
  34. ^ "Say no to expats calling for Saudi citizenship". Arab News. November 24, 2013.
  35. ^ Harrison, Ryan (January 5, 2014). "GCC Citizenship Debate: A Place To Call Home". Gulf Business. Archived from the original on September 1, 2014. Retrieved January 3, 2015.
  36. ^ Elbasnaly, Dina (July 21, 2019). "Bedoons: Kuwait's stateless minority". Deutsche Welle.