There is no number. No treaty or authority anywhere sets a limit on how many citizenships you can have, so the question is never “how many” — it is six separate questions, one per country, each about that country’s own rule for its own citizenship.
For the reader of this site the practical case is two grandparents from two countries and a US passport already in the drawer: three citizenships, from three legal systems that have never spoken to each other about you. None of the six countries here requires you to give up another one to hold its own. What varies is what each expects of you afterwards.
How many citizenships can you have?
As many as the individual countries involved permit, and the arithmetic is done one country at a time. Country A does not care that you also hold C; it cares whether its law lets one of its citizens hold a foreign citizenship, and whether anything you did in acquiring C counts under its law as giving up A.
That is why the count is unstable in both directions. Someone with an Irish, an Italian and a US passport holds three, and each country would tell you the same thing separately: fine. Someone who took a foreign citizenship while a country of theirs still had an automatic-loss rule may hold fewer than they think, and the discovery usually happens at the counter.
The six rules, country by country
The United States. US law permits dual and multiple nationality. A US citizen who acquires another citizenship does not lose US nationality by that act: loss requires a potentially expatriating act performed voluntarily with the intention of relinquishing US nationality, under section 349(a) of the Immigration and Nationality Act. The State Department sets it out on its dual nationality page, along with the obligation that US citizens enter and leave the United States on a US passport. Being recognised as a citizen of Ireland, Canada, Germany, Italy or Poland by descent is not, by itself, an act done with that intention.
Ireland. Irish law does not require you to renounce anything, and does not restrict holding other citizenships. Registration on the Foreign Births Register asks nothing about your other nationalities.
Canada. Canada has permitted multiple citizenship since 1977. A person born abroad who is a Canadian citizen by descent keeps whatever else they hold.
Germany. This is the one that changed recently, and the change is why old pages are wrong. Until the modernisation of the Nationality Act came into force on 27 June 2024, German law generally required a person naturalising to give up their previous citizenship and treated the voluntary acquisition of a foreign citizenship by a German as a loss. Since that date multiple citizenship is generally accepted. Note the distinction that survives: a German by descent under section 4(1) of the Staatsangehörigkeitsgesetz was never naturalising in the first place.
Italy. Italy has permitted dual citizenship since Law no. 91 of 5 February 1992. A recognition under that law asks nothing about your American passport.
Poland. Polish law does not prohibit holding another citizenship, but it does insist on a consequence: in dealings with Polish authorities a Polish citizen is treated as Polish only, and may not rely on a foreign citizenship before them. In practice that means Polish consular formalities are conducted with you as a Pole, whatever else you hold.
What actually constrains you, once you hold three
Not the number. Four other things, and each is a real obligation somewhere.
Which passport at which border. Several countries expect their own citizens to enter and leave on their own passport, the United States among them. Holding three passports is not a choice of which to travel on wherever you like; it is three separate expectations, each of which applies at that country’s own frontier.
Consular protection stops at your own citizenship. The country whose passport you are travelling on cannot usually assist you in a country where you are also a citizen — you are that country’s national there, not a foreign visitor. This is one of the few genuine downsides of a second citizenship, and it is almost never mentioned by anyone selling one.
Military service, where it exists. Conscription is an obligation on citizens, and acquiring the citizenship is what makes it apply. Which countries, at what ages, and whether residence abroad exempts you, is a question for that country’s own authority before you file, not after.
The onward generation. Every citizenship you establish is one your children may inherit, under that country’s own rule — automatically in the declaratory countries, and in Ireland only if you were registered before they were born. Three lines can become three lines for them, or none, depending on dates that are within your control now and not later.
Does a third citizenship put the others at risk?
Almost never today, and the question is worth taking seriously anyway, because the answer was different within living memory.
Ask it in this shape: does the country whose citizenship I already hold have a rule under which acquiring another one costs me this one — and if it once did, when did that rule end? Germany’s ended on 27 June 2024. The United States’ rule was never automatic in that way; it turns on intention.
Where the maths goes wrong
Three situations produce a wrong count, and all three come from treating citizenship as a collection rather than as six separate legal relationships.
- Counting a claim as a citizenship. An entitlement to be registered is not a citizenship. Until the Irish entry is made, it is not one.
- Assuming a country’s current rule applied to an ancestor. Germany permits multiple citizenship now. It did not in 1931, which is why your great-grandfather’s naturalisation ended the line — see where the line breaks.
- Assuming a passport proves a status. An expired passport proves that a country once considered someone its citizen. Whether they still were on a later date is a different question, and it is the one that decides your line.
What to do with the answer
If you have two live lines, work them in the order that protects the most: whichever country’s rule threatens to run out. Italy’s cut-off for the generations outside the new limit and Germany’s declaration window under section 5 both have dates on them, and a claim you can make today may not be one you can make in three years. A Canadian claim under the rule Bill C-3 put in place and an Irish registration have no such clock, beyond the ordinary one that a registration before a child’s birth cannot be made afterwards.
Then read living with two, which is about the part nobody covers: whom the second citizenship is declared to, what does not change, and the child born after the grant. And if what you actually want to know is whether each of those countries will let you keep the American one, the dated country-by-country answer is the next post.