Country guide · Portugal

Does Portugal allow dual citizenship with the USA?

Citizenship-by-Descent.com·Last reviewed November 2026

Educational information only — not legal advice. Always verify with the relevant authority, consulate or registry office.

Yes. Portugal lets you hold Portuguese and US citizenship together, and the same goes for any other country. Descendants claiming through a parent or grandparent don’t give up anything, and neither do Americans who naturalise in Portugal. Under the Nationality Law, a Portuguese citizen loses nationality by declaring that they no longer want it, not by taking another one. The big 2026 reform raised the bar for becoming Portuguese but left that rule in place. Two things are worth watching. Before the 1981 law, taking another nationality voluntarily did end Portuguese nationality, which can affect family lines. And the 2026 law added new words to the article on loss, alongside a criminal penalty bill that the Constitutional Court has twice blocked.

The short answer

  • Portuguese citizen who becomes American today: stays Portuguese. There’s nothing to file.
  • American claiming through a parent or grandparent: keeps US citizenship.
  • American naturalising in Portugal: no renunciation, but ten years’ legal residence since 19 May 2026.
  • Ancestor who naturalised abroad under the old law: lost Portuguese nationality, though article 31 of the current law can reverse that.
  • Someone who wants out: a Portuguese citizen with another nationality can declare that they don’t want to be Portuguese.

What the law says

Portuguese law doesn’t have a sentence saying “dual citizenship is allowed”. The answer comes from what isn’t there, and from four articles of the Nationality Law.

  • Article 8, the only article in the chapter on loss. “Without prejudice to what the law provides, those who, being nationals of another State, declare that they don’t want to be Portuguese lose Portuguese nationality.” You have to hold another nationality, so this can’t make you stateless, and you have to choose it.
  • Articles 1 and 6, the routes in. Neither article 1 (nationality of origin) nor article 6 (naturalisation) lists giving up another nationality among its conditions.
  • Article 27, conflicts. If someone has two or more nationalities and one is Portuguese, only that one counts under Portuguese law.
  • Article 32, forced naturalisation. The Central Administrative Court South decides on loss or keeping of nationality where a foreign state directly or indirectly imposed naturalisation on residents of its territory.

The Constitution frames this. Article 4 says citizens are those treated as such by law or international convention. Article 26(4) says deprivation of citizenship can only happen in cases and on terms set by law, and can’t be based on political motives.

How Portugal got here

  • Before the 1981 law: voluntary acquisition meant loss. Article 31 of today’s law refers to people who “under Law 2098 of 29 July 1959 and earlier legislation lost Portuguese nationality through the voluntary acquisition of a foreign nationality”. Article 30 says the same of women who lost it by marrying under those laws.
  • 3 October 1981: the new Nationality Law. Law 37/81 repealed Law 2098 (article 40). In its first version, article 8 read as it does today, without the opening words added in 2026.
  • 18 May 2026: Lei Orgânica 1/2026. Published with a correction the same day, in force from 19 May. It’s the 13th version of the law.

What the 2026 law changed, and what it didn’t

For dual citizens the headline is what stayed the same. Lei Orgânica 1/2026 added no renunciation requirement and no loss on acquiring another nationality. It did change the following.

  • Residence. Naturalisation now needs seven years for nationals of Portuguese-speaking countries and EU citizens, and ten for everyone else (article 6(1)(b)).
  • Grandchildren. The route in article 1(1)(d) stays. It now requires the conditions in article 6(1)(c) to (h), which cover language and culture, civic knowledge, a solemn declaration of adherence to democratic principles, and conduct checks (article 1(3)). See Portuguese citizenship for grandchildren.
  • Great-grandchildren. The Government may grant nationality to third-degree descendants of Portuguese of origin who have five years’ legal residence (article 6(8)). That’s a discretionary naturalisation.
  • The Sephardic route. The Justice portal says the special regime for descendants of Sephardic Jews was eliminated.
  • Article 8. The words “without prejudice to what the law provides” were added. On their own they create no new way to lose nationality. They leave room for one if another law provides it, which is what the penalty decree below tried to do.

Article 7 of the 2026 law says administrative procedures already pending when it came into force stay under the previous wording.

Still not settled: the criminal penalty

Alongside the reform, Parliament twice approved a change to the Penal Code that would have created loss of nationality as an accessory penalty. It isn’t law. The second version, Decree 49/XVII, would have let a court apply it to a person who also holds another nationality and was sentenced to at least five years in prison for listed crimes committed within 15 years of obtaining nationality.

On 8 May 2026, in ruling 409/2026, the Constitutional Court found the core rule unconstitutional for breaching equality. It also found the listing of crimes such as aggravated homicide, slavery, human trafficking, rape and sexual abuse unconstitutional for breaching proportionality. An earlier version had failed in ruling 1134/2025. Under article 279 of the Constitution, a decree in this position can’t be promulgated unless Parliament removes the provisions or confirms them by a two-thirds majority of deputies present, greater than an absolute majority of deputies in office. The Lisbon Prosecutor’s consolidated Penal Code, updated through Law 53/2026 of 19 August, has no such article. We found no record of a confirmation, but we can’t rule out later moves, so this could change.

The regulation

Article 4 of the 2026 law gave the Government 90 days to update the Nationality Regulation. On 29 October 2026 the Council of Ministers approved a decree-law regulating the new law, covering the language, culture, history and institutions tests and the subsistence requirement. We couldn’t confirm on 6 November 2026 that it had been published, and we haven’t read its text. It affects how you qualify, not whether you can hold two nationalities.

What descendants claiming by descent need to know

Portugal’s tolerance of dual nationality means you don’t risk your US passport by claiming. The real question is whether the line reaches you.

  1. Child of a Portuguese parent. Under article 1(1)(c), you’re Portuguese of origin if your birth is entered in the Portuguese civil register or you declare that you want to be Portuguese. Article 11 says attribution takes effect from birth. See Portuguese citizenship through a parent.
  2. Grandchild. Article 1(1)(d) needs a grandparent of original Portuguese nationality “who has not lost that nationality”, your declaration and ties of effective connection to the national community. This is where the old loss rule bites.
  3. Grandparent who naturalised under the old law. Article 31 says a person who lost nationality this way acquires it again: automatically if no definitive record of the loss was made, unless they declare that they don’t want it, or by declaration if the record exists. Article 31(3) makes that acquisition effective from the date of the foreign naturalisation, without disturbing earlier legal relationships. So the Portuguese birth record matters: look for a note of loss in its margin. The law doesn’t spell out how this works when the ancestor has died or for a grandchild’s claim. Ask the Central Registry or a Portuguese lawyer, and don’t assume either way.
  4. Woman who lost nationality by marriage. Article 30 has the same structure, with effect from the date of marriage.
  5. Great-grandchild. There’s no route from abroad under article 6(8), which requires five years’ legal residence. A parent who qualifies as a grandchild can claim first, and you may then qualify as their child.

Our guide on USCIS naturalisation records shows how to find a naturalisation date.

When US history matters: military and government service

Article 9(1)(c) makes “public functions without a predominantly technical character or non-compulsory military service for a foreign State” a ground for the Public Prosecutor to oppose acquisition of nationality by choice. The prosecutor has two years from registration of the acquisition (article 10). The ground sits in the chapter on acquisition “by effect of will”, which is the section covering children of new citizens, spouses and partners, people who lost nationality as incapable persons, and adoptees. If you’re applying through marriage and served in the US armed forces voluntarily, read this before you file.

Other ways Portuguese nationality can fall away

  • False documents or statements. Under article 12-A, an act giving or removing nationality based on false documents, untrue facts or false declarations is void, unless that would leave the person stateless.
  • The ten-year protection. Under article 12-B, holding Portuguese nationality in good faith for at least ten years consolidates it, even if the act behind it could be declared void. That doesn’t apply if it was obtained by fraud, though third parties in good faith keep theirs.
  • Getting it back after declaring it away. Article 6(6) lets the Government grant nationality to people with effective ties who lost it and never acquired another. Since article 8 requires another nationality, don’t count on an easy way back.

The US side

The State Department’s Foreign Affairs Manual says US citizens who naturalise in another country don’t automatically lose US citizenship, and that an intent to keep it is presumed. Under 8 U.S.C. 1481, US citizenship ends only through a voluntary act done with the intention of giving it up. The Manual also says the US doesn’t encourage dual nationality, that the other country has a predominant claim on you while you’re there, and that you must leave and enter the United States on a US passport, with limited exceptions. Article 27 of the Portuguese law is the same idea from the other direction. See European citizenship by descent for Americans.

Practical steps

  1. Get the ancestor’s full Portuguese birth record and read the marginal notes. A registered loss, or the absence of one, changes your next move.
  2. Find the US naturalisation date and compare it with the 1981 law and with the birth of the next person in your line.
  3. Work out your route. Use the Portuguese citizenship by descent guide and our document chain guide.
  4. Check the regulation before you file. Language and culture proof depends on it.
  5. If you’re applying by marriage, disclose any voluntary military or non-technical government service to your adviser first.

To check whether you have a claim at all, use our free citizenship by descent checker. For other countries, see dual citizenship by descent, country by country, including Spanish dual citizenship.

Frequently asked questions

Does Portugal allow dual citizenship with the USA?

Yes. The Nationality Law doesn’t make a Portuguese citizen choose, and it doesn’t list giving up another citizenship as a condition for becoming Portuguese. A Portuguese citizen who becomes American stays Portuguese unless they declare that they don’t want to be Portuguese. Under Portuguese law, though, only your Portuguese nationality counts (article 27).

Do I have to give up US citizenship to claim Portuguese citizenship by descent?

No. Neither article 1, which covers children and grandchildren born abroad, nor article 6, which covers naturalisation, lists renunciation among its conditions. Article 8 only deals with people who no longer want to be Portuguese. Your US side doesn’t change either, because US law requires a voluntary act done with the intention of giving up US citizenship.

Did Portugal’s 2026 nationality law end dual citizenship?

No. Lei Orgânica 1/2026, in force since 19 May 2026, raised residence periods and tightened requirements, but it didn’t add a renunciation rule or a loss on taking another citizenship. It did add the words “without prejudice to what the law provides” to article 8, the article on loss. A separate decree that would have created loss of nationality as a criminal penalty was found partly unconstitutional in May 2026.

Can Portugal take away my citizenship if I’m a dual citizen?

We found no penalty of that kind in force on 6 November 2026. Parliament approved one twice, and the Constitutional Court found key parts unconstitutional both times, most recently in ruling 409/2026 of 8 May 2026. The Constitution separately limits deprivation to cases set by law and bars political grounds. Nationality based on false documents or statements is a different matter: article 12-A makes that act void.

My grandfather became an American before 1981. Did he lose Portuguese nationality?

Probably, if he took it voluntarily. Article 31 of the current law confirms that people lost nationality this way under Law 2098 of 1959 and earlier law. But the same article brings it back: automatically if no definitive record of the loss was made, unless they declared otherwise, or by declaration if one was made, with effect from the date of the foreign naturalisation. How that works for a descendant’s claim is a question for the Central Registry.

If I’m American and served in the US military, can it block Portuguese citizenship?

It can for some routes. Article 9 lets the Public Prosecutor oppose acquisition by declaration on the ground of non-compulsory military service for a foreign state, or public functions that aren’t mainly technical. That applies to acquisition by choice, such as through marriage, and the prosecutor has two years from registration. Article 1 attribution to children and grandchildren is a different category, so ask the registry about your case.

How long must an American live in Portugal to naturalise?

Ten years of legal residence since 19 May 2026. Nationals of Portuguese-speaking countries and EU citizens need seven. You also have to prove language, culture, history and civic knowledge, make a solemn declaration, meet the conduct conditions and show that you can support yourself. You don’t have to give up US citizenship. Applications already pending on 19 May 2026 stay under the previous law.

Official sources

Checked against these sources on 6 November 2026. The Portuguese texts were read directly and translations are ours. The Diário da República website itself wouldn’t load without a browser, so we read its PDF files, and we couldn’t check there whether the regulation has been published. Only the Central Registry and the Portuguese courts can decide your case; confirm with them or a Portuguese consulate before you rely on this.