How Dual Citizenship Works: Who Allows Two Passports (and Who Doesn't)

3 min read · Updated 1 October 2026

Millions of people around the world legally hold two passports. Some even hold three. But some countries will take your citizenship away the moment you get another one.

This is Countries Compared. Today: how dual citizenship works, who allows it, who doesn't, and the catches nobody tells you about.

First, how do you become a citizen at all?

There are two old rules. The right of soil: you're a citizen of the country where you're born. Most countries in the Americas use it, like Canada, Mexico and Brazil. And the right of blood: you inherit citizenship from your parents, wherever you're born. That's the main rule in most of Europe, Asia and Africa.

Now imagine a child born in Canada to Pakistani parents. Canada says citizen, because of the soil. Pakistan can count the child as a citizen too, by descent. That child can have two nationalities from day one, without doing anything.

The other way is naturalisation. You move to a country, live there for years, pass a language or citizenship test, and apply. And that's where it gets tricky, because some countries make you give up your old passport.

So who says yes?

More and more countries. In 1960, most countries didn't accept dual citizenship. By 2020, according to the MACIMIDE dataset, around three quarters of countries allowed it in some form.

Germany is a big recent example. Since the 27th of June 2024, people who naturalise in Germany can keep their old citizenship. Before that, most non-EU applicants had to give it up.

Pakistan allows dual nationality, but only with a list of specific countries, including the United Kingdom, the United States, and Canada. With other countries, the rules are stricter, so always check the current list first.

And who says no?

China doesn't recognise dual nationality. If a Chinese citizen settles abroad and takes a foreign nationality, they lose Chinese nationality automatically. India doesn't allow it either. Instead, it offers the Overseas Citizen of India card, which gives a lifelong visa, but no vote and no Indian passport. Japan asks people with two nationalities to choose one as young adults.

Now, the benefits.

You can live and work in both countries without a visa. You can travel on whichever passport is stronger. And you can pass both citizenships to your children, depending on the law.

But there are catches.

First, taxes. The United States taxes its citizens wherever they live. So a dual citizen living in Germany may still have to file a US tax return every year. Second, military service. Some countries can call up their citizens even if they hold a second passport. And third, protection. Under a 1930 international convention, a country usually can't protect you against another country that also counts you as its citizen. So in Pakistan, a British Pakistani is usually treated as Pakistani.

In short: Two passports can open a lot of doors. But each one also comes with its own rules.