Requirements via Citizenship & Living in Cambodia
Here's your way of gaining access to a citizenship in Cambodia. Applications for Cambodian citizenship are processed by the Ministry of Interior, and the process generally takes two to three months.
The long route – citizenship by naturalization
Naturalization is the standard alternative for foreigners wishing to become a Cambodian citizen. You will need to have lived in the country for at least seven years with a residence card. On top of being able to speak and write fluently in Khmer, you will also need to have brushed up on your knowledge of Cambodian history. You will have to sit through an exam to prove your proficiency in these areas.
You must also obtain a certification of good behavior and moral conduct by the chief of your commune or quarter, and you need to be in possession of an unblemished criminal record (you will be disqualified if you have committed any criminal offense). Your application must be lodged while currently residing in the Kingdom.
The VIP option – citizenship by investment or donation
Also known as honorary citizenship, this option is usually the subject of some discussion. Officially, an investment of at least 1.25 billion riel ($312,500) in Cambodia, or a donation 1 billion riel or more to the national budget will allow you to bypass the seven-year residence requirement mentioned in the section above. However, you still need to meet the other requirements, including demonstrating fluency in the language.
There are claims that when an investment or a donation of the amounts mentioned above is committed, the citizenship is automatically granted to the investor or donor, whether or not they meet the requirements outlined in the previous section. Currently that still can not confirm nor deny this possibility.
The love path – citizenship by marriage
Came to Cambodia, fell in love, married, had kids – this is the story of many expats around. Fortunately, those bound in holy matrimony are a step closer to citizenship. If you marry a Khmer spouse, you may apply for citizenship after three years of living together, providing the marriage has been properly registered.
The other way – citizenship by birth and descent
Regardless of the place of birth, those born to at least one Khmer parent are entitled to citizenship. Meanwhile, those born in the Kingdom to foreign parents who were born and living legally in Cambodia also acquire Khmer citizenship at birth.
Sources: https://www.b2b-cambodia.com/articles/how-to-obtain-cambodian-citizenship/