Depending on your home country, you may be able to maintain dual citizenship after becoming a US citizen. In recent years, more countries have started officially allowing this. A few countries don’t officially recognize it but also don’t require renouncing their citizenship. Instead, they simply ignore any citizenship you may gain in another country.
Dual citizenship is just as it sounds: holding citizenship in 2 different countries at the same time.
At one time this was uncommon. Most countries allowed you to maintain allegiance to only 1 country. If you wanted citizenship in another, you had to give up your current citizenship. This worked in both directions. Countries required their natural born citizens to give up their citizenship if they wanted citizenship in a different country. Likewise, their new country required they give up citizenship in their country of origin.
This is slowly changing. Many countries now allow (either officially or unofficially) dual citizenship for native-born citizens who want citizenship in the US or another country.
The US allows but doesn’t officially recognize dual citizenship.
Part of the naturalization ceremony for US citizenship seems to ask you to give up your foreign citizenship. But this doesn’t mean you have to give up citizenship in your home country. Instead, it’s a promise to be loyal to the United States if you have to choose between it and another country.
Because the United States doesn’t officially recognize dual citizenship, you must enter and exit the country using your US passport.
In most of these countries double citizenship is only allowed for native-born citizens:
You may be required to enter and leave these countries using their passport.
Some countries don’t officially recognize dual nationalities but often ignore them, rather than force you to give up citizenship. You must usually use your passport from that country to enter and leave that country. These countries include:
China officially forbids dual citizenship but in practice often ignores it.
Many more countries still require you give up your citizenship and relinquish your passport if you become a citizen of another country. These include India, Indonesia, Japan, the Netherlands, Norway, and Singapore, among others.
These lists are not complete, and countries’ laws may change. In addition, sometimes it depends on the relationship between the US and your home country. If you’re unsure of whether you may hold dual citizenship with the US, you may want to check with a representative of your home country’s government before going through with US nationalization.