The short version
- Yes. The United States of America allows dual citizenship. USA.gov says you do not have to choose one nationality, and you can naturalise in another country without risking your US citizenship.
- The other country has to allow it too. Each country makes its own rules.
- Dual citizens must use a US passport to enter and leave the US.
- You lose US citizenship only by doing one of the acts the law lists, on purpose to give it up. Formally renouncing it is one of them.
Does the US allow dual citizenship?
Yes. USA.gov says Americans with dual citizenship do not have to choose one nationality over the other, and that a US citizen may naturalise in another country without risking US citizenship. This holds whether you were born American or became a citizen later.
Dual citizenship, also called dual nationality, means being a citizen of the US and another country at the same time. USA.gov's page on dual citizenship lists what that means for you:
- You owe allegiance to both the US and the other country.
- You must use a US passport to enter and leave the US.
- You do not have to pick one.
US nationality law does not spell out dual nationality. The State Department's Foreign Affairs Manual on dual nationality notes that the Supreme Court called it "a status long recognized in the law" in 1952. The same manual says the US government recognises dual nationality but does not encourage it as a policy, because of the problems it can cause.
Does the other country have to allow dual citizenship?
Yes. Whether you can hold both depends on the other country's law as well as US law. USA.gov tells US citizens to check with the other country's embassy or consulate.
Some countries let you keep your old citizenship when you take a new one, and some do not. Here is what the official sources said when we checked, for six of the countries in our descent checker:
| Country | What the official source says |
|---|---|
| Canada | Americans who are also Canadian can travel to Canada on either passport. |
| Germany | Since 27 June 2024, Germans who apply for another citizenship stay German. |
| Italy | For claims made after 27 March 2025, people who hold another citizenship are recognised by descent only in set cases. |
| Mexico | Registering as Mexican by birth does not affect US nationality. |
| Poland | Under its 1920 law, a Pole who took another citizenship usually stopped being Polish. |
| United Kingdom | Dual citizenship is allowed. You can take another citizenship and stay British. |
Two notes on the table. Canada asks Americans who are also Canadian to carry proof of Canadian citizenship when they travel on the US passport. And Poland's old rule can break a family line today, if an ancestor became American while it applied. If you are thinking about Canada, see how to move to Canada from the US. To see if a parent or grandparent could give you a second citizenship, try our citizenship by descent checker.
How can Americans lose US citizenship?
Only by doing one of the acts the law lists, voluntarily and with the intention of giving up US nationality. Taking a second citizenship is not enough on its own.
The law, 8 U.S.C. 1481, lists acts such as:
- Naturalising in another country, at 18 or older.
- Taking an oath of allegiance to another country, at 18 or older.
- Serving in a foreign army that is fighting the US, or serving in any foreign army as a commissioned or non-commissioned officer.
- Taking some jobs in a foreign government.
- Formally renouncing US nationality before a US consular officer abroad.
- Being convicted of treason or related crimes.
Each one counts only if done on purpose to give up US nationality. The State Department says that when a US citizen naturalises abroad or takes a routine oath of allegiance, it presumes the person meant to keep US citizenship. They do not need to prove it. A person who tells a consular officer that they did mean to give it up will lose it.
To renounce, you sign an oath at a US embassy or consulate abroad. USA.gov says that after renouncing you may still owe tax payments, and you may need a visa to come back to the US.
Which passport do dual citizens use for the US?
A US passport. USA.gov says dual citizens must use a US passport to enter and leave the US. The State Department's manual cites the law behind it, 8 U.S.C. 1185(b), with limited exceptions.
The other country may have its own version of this rule:
- Mexico: its nationality law says Mexicans by birth must enter and leave Mexico as Mexicans, even if they hold another nationality.
- United Kingdom: GOV.UK says dual nationals can travel to the UK on a UK or Irish passport, or with a certificate of entitlement.
- Canada: IRCC says most dual Canadian citizens need a Canadian passport to travel to Canada. Americans who are also Canadian can use either passport.
So many dual citizens carry two passports. Each one has its own list of countries you can visit without a visa. Compare them in our passport ranking, or start with where a US passport gets you in without a visa.
Do dual citizens still pay US tax?
US citizens, dual or not, are taxed on their worldwide income, the IRS says. Its page for Americans abroad says the filing rules are generally the same whether you live in the US or abroad.
The IRS also says many Americans abroad qualify for benefits like the foreign earned income exclusion and the foreign tax credit, but only by filing a US return. Our guide to the foreign earned income exclusion explains how that one works.
The other country can have its own tax rules for its citizens too. The State Department's manual lists taxes and military service as burdens dual nationality can bring.
Can the US help dual citizens abroad?
Yes, but its help can be limited in the other country of your citizenship. The State Department's manual says that when a dual citizen is in that country, that country has the main claim on them.
The manual says US consular staff still step in for every US citizen, and that staff tell dual nationals their help may be limited. It also warns that a country may treat a dual national only as its own citizen, for example one who travels on that country's passport.
Other countries work the same way. GOV.UK, for example, says British dual nationals cannot get diplomatic help from the UK while they are in their other country of citizenship.