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Dual Citizenship in the U.S.: 9 Things Every Applicant Should Know

By USILT Editorial Team · Published June 10, 2026 · Last verified June 2026

Dual citizenship — holding U.S. citizenship and the citizenship of another country at the same time — is one of the most searched and most misunderstood topics in U.S. immigration. The short answer is that the United States does allow it: U.S. law does not require a naturalized citizen to give up their original nationality, and it does not force you to choose. But "allowed" is not the same as "simple." Your other country may have very different rules, and dual status carries obligations most people never think about until they hit one. Here are nine things to understand before you assume you can hold two passports.

1. The U.S. permits dual citizenship — it just doesn't mention it

There is no single statute that "grants" dual citizenship. Instead, U.S. law is simply silent on the question, and the U.S. Supreme Court has held that a person can owe allegiance to more than one country. When you naturalize, the United States does not ask your home country to cancel your citizenship, and it does not report your naturalization to them. Whether you keep your original citizenship is determined almost entirely by the other country's law, not U.S. law.

2. Your other country decides whether you keep its citizenship

This is the part that catches people off guard. Some countries automatically strip citizenship from anyone who naturalizes elsewhere; others allow dual nationality freely; and some require you to formally apply to retain it. India, China, Japan, and several others generally do not permit dual citizenship for adults, while Canada, the U.K., Ireland, Mexico, and many EU countries do. Always check your country of origin's rules before you assume you will keep that passport.

3. The Oath of Allegiance does not automatically cancel your old citizenship

During naturalization you take the Oath of Allegiance, which includes renouncing "allegiance and fidelity" to any foreign state. Many applicants worry this legally terminates their original citizenship. In practice, the Oath is a U.S. requirement and does not, by itself, cause another country to revoke your status — only that country can do that under its own law. The Oath expresses loyalty to the United States; it is not a renunciation filing with your home country.

4. Dual citizens must enter and leave the U.S. on a U.S. passport

By law, a U.S. citizen — including a dual citizen — must use a U.S. passport to enter and depart the United States. You can absolutely use your other passport to enter your other country of citizenship. Many dual nationals legitimately travel with two passports: the U.S. one for U.S. borders and the foreign one for the foreign country. Using the wrong document at a U.S. port of entry causes unnecessary delays.

5. You owe U.S. taxes no matter where you live

The United States taxes its citizens on worldwide income regardless of where they reside. A dual citizen living abroad still files a U.S. tax return every year, and may also have foreign bank account reporting (FBAR/FATCA) obligations. Tax treaties and the Foreign Earned Income Exclusion often prevent double taxation, but the filing requirement does not disappear simply because you live in your other country. This is the single most common surprise for new dual citizens.

6. "Why dual citizenship is bad" — the real downsides

People search this phrase constantly, so it deserves a straight answer. The genuine downsides are: ongoing U.S. tax filing from abroad, potential military or civic obligations in the other country, the complexity of two legal systems, and the risk that the other country will not provide U.S. consular protection if you are detained there. For most people these are manageable; for a few — especially those in countries with mandatory military service — they are significant.

7. Children can be dual citizens from birth

A child born in the United States is a U.S. citizen by birthright, and may simultaneously acquire the citizenship of a parent's country by descent. A child born abroad to a U.S.-citizen parent can acquire U.S. citizenship while also being a citizen of the country of birth. In these cases, dual citizenship arises automatically at birth rather than through naturalization — no application is required.

8. Dual citizenship does not require giving up your green card status — it replaces it

Naturalization converts a lawful permanent resident into a U.S. citizen. Once you naturalize, you are no longer a green card holder; you hold the stronger status of citizen, which cannot be lost through time abroad and is not subject to the residence and travel limits that bind green card holders. If you are weighing whether to naturalize, see how citizenship compares to permanent residence.

9. You can renounce later — but it is permanent and costly

If dual status becomes a burden (most often for tax reasons), you can formally renounce U.S. citizenship at a U.S. consulate. Renunciation is deliberate, irreversible, and currently carries a substantial State Department fee, plus a possible "exit tax" for higher-net-worth individuals. Because it cannot be undone, renunciation should never be a casual decision — and it is rarely necessary for ordinary dual citizens.

The United States lets you keep two citizenships. The hard questions are almost always about your other country — and your taxes.

The Bottom Line

Dual citizenship is fully permitted under U.S. law, and millions of Americans hold it. The decisions that actually matter are made elsewhere: your country of origin's rules on retaining its nationality, your ongoing U.S. tax obligations, and how you travel. Before you naturalize, confirm what your home country allows, and talk to a tax professional about worldwide-income filing. For citizenship questions specific to your case, consult a licensed U.S. immigration attorney.

Frequently Asked Questions

Does the U.S. allow dual citizenship?

Yes. U.S. law permits dual (and even multiple) citizenship. The United States does not require naturalized citizens to renounce their original nationality, and it does not ask your home country to cancel it. Whether you actually keep your other citizenship depends on that country's own law.

Do I have to give up my original passport to become a U.S. citizen?

Not under U.S. law. The Oath of Allegiance is a U.S. requirement and does not cancel your foreign citizenship — only your home country can do that. Some countries, however, automatically revoke citizenship when you naturalize elsewhere, so check your country's rules.

Do dual citizens pay U.S. taxes if they live abroad?

Yes. The U.S. taxes citizens on worldwide income regardless of residence. Dual citizens living overseas must still file a U.S. return and may have foreign account reporting duties, though tax treaties and exclusions often prevent actual double taxation.

Which countries do not allow dual citizenship?

Rules change, but countries that have generally restricted dual citizenship for adults include India, China, and Japan, among others. Many countries — Canada, the U.K., Ireland, Mexico, and most of the EU — do allow it. Always verify with your home country's authorities.

Which passport should a dual citizen use to travel?

Use your U.S. passport to enter and leave the United States — this is legally required. You can use your other passport to enter your other country of citizenship. Carrying both is common and legitimate.

Is dual citizenship worth it?

For most people, yes — it preserves ties to your home country while giving full U.S. rights. The main trade-offs are ongoing U.S. tax filing and any obligations your other country imposes. Weigh these against the benefits for your situation.

This article is for informational purposes only and does not constitute legal advice. Immigration law is complex and fact-specific. Consult a licensed U.S. immigration attorney for guidance on your individual case.