U.S. dual citizenship laws are unusual in that they barely exist as written law: no federal statute authorizes, defines, or forbids holding two nationalities, and the government simply recognizes the status when another country’s laws also claim you as a citizen.1U.S. Department of State. Dual Nationality What that permission comes with is a set of real, ongoing obligations, mostly around taxes, financial reporting, travel documents, and the limits of American consular help abroad. Understanding those is the whole practical picture.
Is Dual Citizenship Legal in the United States
Yes. Federal law never mentions dual citizenship by name, and the Supreme Court’s 1967 ruling in Afroyim v. Rusk established that the government cannot involuntarily strip an American of citizenship: it can only be lost through a voluntary act done with the intent to give it up.2Library of Congress. Afroyim v. Rusk, 387 U.S. 253 Acquiring a second citizenship, voting in a foreign election, or serving in a foreign military does not by itself cost you your U.S. passport.
The oath a naturalized citizen takes creates a common misunderstanding. It asks the applicant to “renounce and abjure absolutely and entirely all allegiance and fidelity to any foreign prince, potentate, state, or sovereignty.”3Office of the Law Revision Counsel. 8 USC 1448 – Oath of Renunciation and Allegiance Despite the wording, the United States does not enforce abandonment of the other citizenship. Whether you keep it depends entirely on the other country’s laws.
How People End Up With Two Citizenships
At Birth
The most common route is automatic. The United States grants citizenship to nearly anyone born on its soil. Many other countries grant citizenship by descent, through a parent’s bloodline, regardless of where the birth happens. A child born in the U.S. to parents who hold citizenship elsewhere often qualifies for both at once, with no application required and no forced choice at adulthood.
Through Naturalization or Marriage
Adults acquire a second citizenship by naturalizing in another country while keeping the first. U.S. naturalization requires at least five years of continuous permanent residence, physical presence for at least half that time, and a showing of good moral character.4Office of the Law Revision Counsel. 8 USC 1427 – Requirements of Naturalization Other countries set their own timelines, often three to five years, sometimes with language or financial requirements. Marriage to a foreign national frequently opens an accelerated route with shortened residency.
Passing U.S. Citizenship to a Child Born Abroad
If you are a U.S. citizen and your child is born in another country, your child may acquire American citizenship at birth, but only if you meet specific physical-presence requirements. When one parent is a U.S. citizen and the other is not, the American parent must have been physically present in the United States for at least five years before the child’s birth, with at least two of those years after age 14.5Office of the Law Revision Counsel. 8 USC 1401 – Nationals and Citizens of the United States at Birth Time on U.S. military service or federal government work abroad counts.
When both parents are U.S. citizens, the bar is lower: only one parent needs to have lived in the United States at some point before the child’s birth. If the citizen parent falls short of the physical-presence threshold, the child does not automatically acquire citizenship and would need a separate naturalization process. This catches second-generation Americans who grew up mostly overseas. If you are planning to have children abroad, verify your own physical-presence history first.
Tax Obligations for Dual Citizens
The United States taxes based on citizenship, not residence. As an American citizen you owe the IRS an annual return reporting worldwide income, even if every dollar was earned abroad and you have not set foot in the U.S. all year.6Internal Revenue Service. U.S. Citizens and Resident Aliens Abroad Only one other country in the world, Eritrea, does this.
Relief From Double Taxation
Two mechanisms prevent full taxation by both countries on the same income. The foreign earned income exclusion lets qualifying taxpayers exclude up to $132,900 of foreign earnings from U.S. taxable income for tax year 2026.7Internal Revenue Service. Figuring the Foreign Earned Income Exclusion To qualify you need to either pass a physical-presence test of 330 days abroad in a 12-month period, or be a bona fide resident of a foreign country for a full tax year. The foreign tax credit lets you offset U.S. tax with income tax already paid to another country, and U.S. income tax treaties with dozens of countries can resolve dual-residency situations.8Internal Revenue Service. Tax Treaties Many dual citizens abroad end up owing little or no U.S. tax, but the filing itself is not optional. Skipping the return creates penalties even when the balance due is zero.
Foreign Bank and Asset Reporting
Beyond the tax return, if your foreign bank or investment accounts together exceed $10,000 at any point during the year, you must file a Report of Foreign Bank and Financial Accounts (FBAR) with the Financial Crimes Enforcement Network.9Internal Revenue Service. Report of Foreign Bank and Financial Accounts (FBAR) This is separate from the tax return and easy to overlook. The penalty for a non-willful failure to file now exceeds $16,000 per form after inflation adjustments. Willful violations carry civil penalties up to the greater of $100,000 or 50% of the account balance, plus criminal exposure of up to $250,000 in fines and five years in prison.
A separate rule under the Foreign Account Tax Compliance Act adds Form 8938 for higher-value foreign assets. Thresholds depend on where you live and how you file. A single filer inside the United States must report when foreign financial assets exceed $50,000 on the last day of the year or $75,000 at any point during the year. For a single filer living abroad, those thresholds rise to $200,000 and $300,000. Joint filers get higher thresholds in both cases.10Internal Revenue Service. Summary of FATCA Reporting for U.S. Taxpayers Filing the FBAR does not excuse Form 8938, and vice versa. They cover overlapping but distinct categories of assets.
Passports, Selective Service, and Foreign Military Duty
Federal law requires U.S. citizens to carry and use a valid U.S. passport when entering or leaving the country.11Office of the Law Revision Counsel. 8 USC 1185 – Travel Control of Citizens and Aliens If you hold two passports, use the American one at the U.S. border. You can present the foreign one when entering the other country of citizenship. Trying to enter the U.S. on a foreign passport can trigger delays and additional screening at the port of entry.
Male dual citizens between 18 and 25 who live in the United States must register with the Selective Service System within 30 days of their 18th birthday, regardless of their other nationality.12Selective Service System. Who Needs to Register? Registration is not a draft. There has been no active draft since 1973, and the registry only places your name on file. Failing to register can disqualify you from federal student aid, government employment, and naturalization benefits.
Some countries impose their own military service on all citizens, including those abroad. If your other country has conscription, your American citizenship does not exempt you from it.
Consular Protection Has Limits
If you run into legal trouble in the country of your other nationality, the U.S. government may not be able to help you. Under a widely recognized principle of international law, when you are physically in a country that considers you its citizen, that country has the primary claim on your allegiance and can treat you as a local national. It does not have to acknowledge your American citizenship at all.13U.S. Department of State Foreign Affairs Manual. 7 FAM 080 Dual Nationality
Local police may not notify the U.S. embassy if you are detained, and even if you request consular access, the embassy may be denied permission to visit.14U.S. Department of State. Dual Nationality The risk is highest when you enter the other country on that country’s passport rather than your U.S. passport, because local authorities may have no record that you hold American citizenship.
Social Security Across Two Systems
Dual citizens who split a career between two countries can end up short of the credits needed to qualify for benefits in either system. Totalization agreements solve this by letting you combine work credits from both countries to meet eligibility. The United States has these agreements with roughly 30 countries, including Canada, the United Kingdom, Germany, Japan, Australia, and most of Western Europe.15Social Security Administration. U.S. International Social Security Agreements They also prevent paying into two social security systems on the same earnings, by designating which country’s system covers you based on work location and assignment length. If your other country lacks a totalization agreement with the U.S., plan carefully to avoid coverage gaps or duplicate contributions.
One recent change matters for retirees with foreign pensions. The Windfall Elimination Provision, which used to reduce U.S. Social Security benefits for people who also received a foreign pension from work not covered by Social Security, no longer applies. Benefits payable from January 2024 forward are not reduced, and anyone whose benefits were previously reduced is being paid back.16Social Security Administration. Pensions and Work Abroad Won’t Reduce Benefits
Giving Up U.S. Citizenship
Citizenship can be lost only through specific voluntary acts listed in the Immigration and Nationality Act, and only when performed with the intent to relinquish nationality.17Office of the Law Revision Counsel. 8 USC 1481 – Loss of Nationality by Native-Born or Naturalized Citizen The listed acts include formally renouncing before a U.S. consular officer abroad, serving as a senior official in a foreign government, and joining a foreign military engaged in hostilities against the United States. Accidentally doing something on the list does not cost you citizenship. The government must show you specifically meant to give it up.
Formal renunciation is the most common voluntary path. You appear at a U.S. embassy or consulate abroad, sign an oath of renunciation, and the State Department reviews the case. If approved, the government issues a Certificate of Loss of Nationality. As of April 13, 2026, the fee dropped from $2,350 to $450.18Federal Register. Schedule of Fees for Consular Services – Fee for Administrative Processing of Request for Certificate of Loss of Nationality
The Exit Tax
Renouncing does not necessarily end your financial relationship with the IRS. If you qualify as a “covered expatriate,” the government imposes an exit tax that treats your worldwide assets as if you sold them the day before you gave up citizenship. You are a covered expatriate if your net worth is $2 million or more on the date of expatriation, or if your average annual net income tax liability over the prior five years exceeds an inflation-adjusted threshold (the 2025 figure was $206,000).19Internal Revenue Service. Expatriation Tax You also qualify if you cannot certify five years of tax compliance before expatriation. The tax applies to unrealized gains across your whole portfolio, not just U.S.-based assets, so the bill can be substantial. Work through the numbers with an international tax professional well before scheduling the consular appointment.