Almost 50% of Luxembourg’s population was born somewhere else. Barely 1% of Mexico’s was. Between those two extremes sits every other country on Earth, and the single statistic that lets you compare them meaningfully is not citizenship, immigration status or nationality, but something simpler: where a person was actually born. Foreign-born population, the count of residents born outside the country where they now live, has become the standard international measure for comparing migration’s footprint across countries with wildly different citizenship laws, and understanding why it is preferred over citizenship-based counts is the key to reading migration statistics correctly.
What Does Foreign Born Population Mean?
A foreign-born person is anyone living in a country other than the one in which they were born. That single, stable fact, place of birth, does not change over the course of a person’s life, unlike citizenship, which can be acquired, renounced or inherited according to rules that vary enormously from country to country. This is precisely why the United Nations and the OECD both treat foreign-born status as the standard for measuring immigrant populations internationally: it produces a comparable figure regardless of how generous or restrictive a given country’s naturalization laws happen to be.
The foreign-born category deliberately spans several very different kinds of people: naturalized citizens who arrived decades ago and have since taken the citizenship of their new country, permanent residents who have not naturalized, temporary workers and students, and undocumented migrants, to the extent censuses and surveys can capture them. It is a status defined entirely by birthplace, not by legal permission to remain, intention to stay permanently, or current passport.
How Large Is the Foreign Born Population Worldwide?
The global foreign-born population aligns closely with the broader international migrant stock figure of 304 million recorded by the UN for 2024, since migrant stock estimates are themselves built primarily from foreign-born population data wherever countries collect it.
Within that global total, OECD countries account for a disproportionate share: more than 160 million foreign-born people lived in OECD member countries in 2024, meaning the OECD’s 38 mostly high-income countries host more than half of the world’s entire migrant population despite representing a much smaller fraction of the world’s countries and, in many cases, of the world’s total population. The United States alone accounted for close to a third of all foreign-born residents living across the entire OECD.
Global and OECD Foreign-Born Population, 2024
| Measure | Figure |
|---|---|
| Global international migrant stock (foreign-born, approx.) | 304 million |
| Foreign-born population across OECD countries | 160+ million |
| OECD share of global migrant stock | over 50% |
| US share of OECD’s foreign-born population | ~33% |
| Average foreign-born share, OECD countries, 2024 | 11.5% |
| Average foreign-born share, OECD countries, 10 years earlier | 9.1% |
Source: OECD, International Migration Outlook 2025.
The OECD average foreign-born share rose from 9.1% to 11.5% over the decade to 2024, a meaningful structural increase across the world’s wealthiest economies taken as a group, even though individual countries within that average moved very differently, some rising sharply, a handful actually declining.
Countries With the Largest Foreign Born Populations
Ranked by absolute numbers, the foreign-born population map closely tracks the broader migrant destination rankings, concentrated in a small number of large, high-income countries.
Largest Foreign-Born Populations by Country
| Rank | Country | Foreign-Born Population (approx.) |
|---|---|---|
| 1 | United States | 52 million |
| 2 | Germany | 17 million |
| 3 | Saudi Arabia | 14 million |
| 4 | United Kingdom | 12 million |
| 5 | France | 9 million |
Source: UN DESA, International Migrant Stock 2024, foreign-born-based estimates.
Countries With the Highest Foreign Born Shares
Switch to percentage terms and, as with the broader immigrant-share rankings, an almost entirely different group of countries rises to the top, dominated by Gulf states and small, wealthy European economies.
Highest Foreign-Born Population Shares
| Country | Foreign-Born Share of Population | Approx. Year |
|---|---|---|
| Vatican City (Holy See) | ~100% | — |
| United Arab Emirates | ~83-89% | 2020s |
| Qatar | ~65-78% | 2017-2024 |
| Kuwait | ~67-75% | 2020s |
| Bahrain | ~52% | 2020s |
| Luxembourg | ~47-51% | 2022-2024 |
| Singapore | ~43-46% | 2020s |
| Switzerland | ~25-31% | 2022 |
| Australia | ~28-31.5% | 2022-2024 |
| New Zealand | ~25%+ | 2022 |
Note: figures vary across sources due to differing reference years and whether the source measures foreign-born or foreign-citizen population; the Holy See’s 100% figure reflects that it has essentially no native-born resident population by the nature of its clergy-based population.
Within the OECD specifically, the pattern is unambiguous: Australia, Luxembourg, New Zealand and Switzerland were the only OECD members where at least one in four residents was foreign-born as of the most recent comparative data, with Luxembourg alone approaching 50%.
At the opposite extreme, only three OECD countries, Japan, Mexico and Poland, had a foreign-born share below 3%, illustrating just how wide the range runs even among a group of otherwise broadly comparable high-income economies.
Lowest Foreign-Born Shares Among OECD Countries
| Country | Foreign-Born Share |
|---|---|
| Mexico | ~1% |
| Poland | ~2.2% |
| Japan | ~2.5% |
| South Korea | ~3.8% |
| Türkiye | ~3.5% |
Source: Statista, “Foreign-Born or Home-Grown?” OECD 2023 data.
Where Foreign Born Communities Come From
Origin patterns for foreign-born populations mirror the broader emigration data covered elsewhere in this series: India, China and Mexico anchor the largest single-country origin flows globally, while smaller but fast-growing origin populations, notably Ukraine, Venezuela and Afghanistan, reflect recent conflict and political crisis rather than established, decades-long labor corridors.
Within specific destination countries, origin composition can be dominated by a single neighboring or historically linked country, as with Malaysian migrants making up 44% of Singapore’s entire foreign-born population, or spread across a much wider set of source countries, as in the United States, where Mexican-born residents form the largest single group but represent a minority of the country’s overall foreign-born total.
By world region, Oceania records the highest regional share of foreign-born residents, around 21%, reflecting the outsized influence of Australia and New Zealand’s high immigrant shares on a comparatively small regional population base.
Foreign Born Population by Age and Sex
Foreign-born populations, like international migrants generally, concentrate heavily in working-age brackets, since labor migration and family formation remain the dominant drivers of movement across borders globally.
The OECD notes that around 17% of immigrants across its member countries had lived in their host country for five years or less as of the most recent comparative period, indicating that even in mature, high-share destination countries, a meaningful share of the foreign-born population reflects comparatively recent arrival rather than only long-settled communities.
Sex composition varies by destination system in the same pattern documented for the broader migrant population: female-majority in most European and North American destinations, tied to family reunification and care-work migration, and male-majority across Gulf Cooperation Council states, tied to construction, energy and security sector labor recruitment.
Foreign Born Versus Foreign Citizen
These two measures answer genuinely different questions, and the gap between them can be large. Foreign-born counts people by where they were born, regardless of their current citizenship. Foreign citizen (or foreign national) counts people by their current legal citizenship, regardless of where they were born. A foreign-born person who has since naturalized no longer counts as a foreign citizen but remains foreign-born permanently.
Conversely, in countries where citizenship passes strictly by descent rather than birthplace (jus sanguinis systems), a person can be born within the country to non-citizen parents and count as a foreign citizen despite being native-born in every practical sense.
The OECD’s own indicator documentation makes this distinction explicit: “the foreign population consists of people who still have the nationality of their home country [and] may include people born in the host country,” while the foreign-born population is “substantially larger than the share of foreign nationals” in most countries, because it also captures everyone who has since naturalized.
Because the gap between these two measures depends entirely on each country’s specific citizenship and naturalization rules, comparing a foreign-citizen figure from one country against a foreign-born figure from another produces a misleading result, even when both numbers are individually accurate.
Illustrative Comparison: Why the Two Measures Diverge
| Scenario | Counted as Foreign-Born? | Counted as Foreign Citizen? |
|---|---|---|
| Person born abroad, later naturalized | Yes | No |
| Person born abroad, still holds original citizenship | Yes | Yes |
| Person born in-country to foreign-citizen parents, in a jus sanguinis system | No | Possibly, depending on national law |
| Person born in-country to foreign-citizen parents, in a jus soli system | No | No (typically acquires citizenship at birth) |
How Foreign Born Populations Have Changed
The trajectory of foreign-born populations across the OECD has moved firmly upward over the past decade: the average foreign-born share across member countries rose from 9.1% to 11.5% in the ten years to 2024, and the underlying share increased in nearly every OECD country over the past decade, with the exceptions being Greece, Israel and the Baltic states, where it declined or held roughly flat.
Naturalization has kept pace with this growth: acquisitions of citizenship in OECD countries reached historically high levels in 2024, approaching 3 million according to partial data, with Germany granting citizenship to 290,000 foreign residents and the United Kingdom to 270,000, both record totals for their respective countries. India was the leading single source of new OECD citizenships in 2023, with 225,000 Indian citizens acquiring an OECD nationality, a record, followed by Syria at 150,000, also a record, a figure that reflects both the country’s large refugee-origin diaspora and the length of time many Syrian refugees have now spent in host countries, reaching eligibility for naturalization.
Why Foreign Born Statistics Matter
Foreign-born population data underpins several distinct policy and analytical uses that a simple migrant headline count cannot support on its own. It allows internationally comparable measurement of migration’s demographic footprint, since it does not depend on any single country’s citizenship rules.
It captures the true scale of naturalized communities that citizenship-only statistics would otherwise miss entirely, since a naturalized citizen effectively disappears from foreign-national counts while remaining fully visible in foreign-born data. It supports labor market analysis, since foreign-born workers, particularly recent arrivals within their first five years in a country, often show distinct employment patterns from both long-settled foreign-born residents and the native-born population.
And, in countries facing population aging or decline, foreign-born population trends offer one of the clearest available indicators of how much international migration is currently contributing to sustaining or shrinking the working-age population base.
Key Findings
- The global foreign-born population aligns closely with the broader international migrant stock of 304 million recorded for 2024, with OECD countries alone hosting more than 160 million, over half the world’s total.
- The average foreign-born share across OECD countries rose from 9.1% to 11.5% over the decade to 2024, a meaningful structural increase across the world’s wealthiest economies as a group.
- Luxembourg has the highest foreign-born share of any OECD country, close to 50%, followed by Australia, New Zealand and Switzerland, all above 25%.
- Only three OECD countries, Japan, Mexico and Poland, have a foreign-born share below 3%, the widest gap of any comparable set of high-income economies.
- OECD citizenship acquisitions reached historic highs in 2024, approaching 3 million, with Germany (290,000) and the United Kingdom (270,000) both posting record naturalization totals.
- The foreign-born and foreign-citizen measures diverge meaningfully in most countries, since a foreign-born person who naturalizes remains foreign-born permanently while no longer counting as a foreign citizen.
Frequently Asked Questions
1. What does foreign born mean?
Foreign-born describes anyone living in a country other than the one in which they were born, regardless of their current citizenship, immigration status or how long they have lived there.
2. Which country has the largest foreign born population?
In absolute numbers, the United States has the largest foreign-born population of any country, about 52 million people, roughly a third of the entire OECD’s foreign-born total on its own.
3. Is foreign born the same as immigrant?
In most everyday usage, yes, “foreign-born” and “immigrant” are treated as synonyms, and both the UN and OECD use foreign-born status as their standard definition for measuring immigrant populations internationally.
4. What is the difference between foreign born and foreign citizen?
Foreign-born measures where a person was born and never changes over their lifetime. Foreign citizen (or foreign national) measures current legal citizenship, which can change through naturalization. A naturalized citizen remains foreign-born but is no longer a foreign citizen.
5. Which country has the highest foreign-born population share?
Among sovereign states with substantial populations, the United Arab Emirates and Qatar post the highest foreign-born shares in the world, both in the range of roughly two-thirds to nearly nine-tenths of their total population depending on source and year.
6. Which OECD country has the highest share of foreign-born residents?
Luxembourg has the highest foreign-born share among OECD countries, at close to 50%, followed by Switzerland, Australia and New Zealand, all above 25%.
7. Which countries have the lowest foreign-born shares?
Among OECD members, Mexico (about 1%), Poland (about 2.2%) and Japan (about 2.5%) have the lowest foreign-born shares of any comparably developed economies.
8. Why does the foreign-born measure matter more than citizenship for international comparisons?
Because citizenship rules vary enormously by country, some grant it easily through birthplace, others make naturalization difficult or restrict it by descent, a citizenship-based count would not be comparable across countries. Foreign-born status is fixed at birth and unaffected by these legal differences, making it the internationally preferred measure.
9. Is the foreign-born population growing?
Yes, broadly. The average foreign-born share across OECD countries rose from 9.1% to 11.5% over the decade to 2024, increasing in nearly every member country except Greece, Israel and the Baltic states.
10. How many people gained citizenship in a new country recently?
Citizenship acquisitions across OECD countries approached 3 million in 2024, a historic high, with Germany and the United Kingdom both recording their largest-ever annual totals.
Sources
- OECD, International Migration Outlook 2025, “Recent developments in international migration movements and labour market inclusion of immigrants,” November 2025
- OECD, “Foreign population” and “Stocks of foreign-born population in OECD countries,” data indicators
- OECD, Society at a Glance 2024: OECD Social Indicators, “Migration” chapter, June 2024
- United Nations Department of Economic and Social Affairs (UN DESA), Population Division, International Migrant Stock 2024: Key facts and figures, 2025
- Visual Capitalist, “Charted: The Share of Foreign-Born Population in OECD Countries,” 2025
- Statista, “Foreign-Born or Home-Grown?” citing OECD 2023 data
- Wikipedia/UN definitional sourcing, “Foreign born,” citing UN DESA and US Census Bureau methodology notes
