How to Acquire Belgian Nationality: Declarations and Requirements

The main way to acquire Belgian nationality as an adult is by filing a nationality declaration under Article 12bis of the Belgian Nationality Code after five years of uninterrupted legal residence, meeting language, integration, and economic participation requirements. The registration fee is €1,030 for declarations filed from February 20, 2026 onward, and once your municipality accepts the file, the Public Prosecutor has four months to review it before you become Belgian.¹

Naturalization by Parliament still exists, but it is reserved for narrow cases. For almost everyone, the declaration is the route.

Who Is Already Belgian Without Applying

Before starting an application, check whether you already qualify by birth. If at least one of your parents is Belgian and was born in Belgium, you are Belgian automatically from birth, wherever you were born.

If your Belgian parent was born outside Belgium, nationality does not pass automatically. Your parent has to file a Declaration of Attribution of Belgian Nationality at a Belgian consular post before you turn five. Miss that window and this route closes entirely.²

Children born in Belgium to two foreign-born parents can also become Belgian through a declaration filed before age twelve, provided at least one parent has ten years of legal residence and an unlimited residence permit, and the child has lived in Belgium continuously since birth.³

The Five-Year Declaration for Adults

This is the standard adult route. You need five years of uninterrupted legal residence in Belgium, registered in either the Foreigners’ Register or the Population Register, and you must satisfy three additional tests.

Language. Show at least A2-level proficiency in Dutch, French, or German under the Common European Framework of Reference for Languages. Certificates from SELOR, VDAB, Actiris, FOREM, or the Arbeitsamt qualify, as does a diploma from a Belgian educational institution.

Social integration. Prove it one of three ways: an upper secondary diploma from a Belgian institution, at least 400 hours of recognized vocational training, or completion of an integration course from the competent regional authority.

Economic participation. Show that you worked at least 468 days during the five years before your application, as an employee or as a self-employed person paying quarterly social security contributions.

All three conditions have to be met. The 468-day test is where most applications get stuck, because gaps in employment history or missing social security records can sink an otherwise complete file.⁴

The Ten-Year Alternative

If you cannot meet the 468-day work requirement but have lived legally in Belgium for ten years, the rules loosen. You still need A2 language proficiency, but instead of counting work days or completing a formal integration course, you can demonstrate participation in the economic or socio-cultural life of your community by any legal means, including volunteer work or community involvement.⁵

Reduced Requirements by Category

Spouses and Partners of Belgian Citizens

If you are married to or in a registered cohabitation with a Belgian, and you have lived together in Belgium for at least three years at the time of the application, the work requirement drops from 468 to 234 days over the previous five years, combined with a 400-hour vocational training program. You can also satisfy the integration test through a diploma or integration course instead. Five years of legal residence is still required. Parents of a Belgian minor child get the same reduced work threshold.⁴

Retirees and People With a Recognized Disability

Applicants who have reached retirement age, or who have a recognized disability or medical condition that prevents them from working, are exempt from the language, integration, and economic participation tests entirely. Five years of legal residence is the only substantive requirement.⁵

Foreign Nationals Born in Belgium

If you were born in Belgium and have lived there continuously until eighteen, you only need to be at least eighteen and legally resident. Language, integration, and work requirements do not apply.⁵

Documents You Need to Gather

Every document issued abroad must be translated into Dutch, French, or German by a sworn translator and legalized with an apostille or through the Belgian consulate in your country of origin. The core file includes:

A certified birth certificate from your country of origin, translated and legalized.
A residence history certificate from your municipality (commune or gemeente) confirming the length and legality of your stay.
Proof of economic participation: social security statements, employment contracts, or self-employment records adding up to the required number of work days.
An A2 language certificate from a recognized testing body, or a diploma from a Belgian institution.
Proof of social integration: a diploma, vocational training certificate, or integration course completion.

Every claim on the declaration form has to be backed by a matching official document. Municipal clerks check for completeness before accepting the file, and incomplete submissions come straight back.

Filing the Declaration and What Happens Next

You file in person with the Civil Status Officer at the municipality where you are registered. Pay the €1,030 registration fee in advance and include proof of payment in your file. Nationality applications for minor children are free.¹

Once the officer accepts the file and issues a receipt, a four-month review period starts. The Public Prosecutor checks your background for issues related to public order, national security, and fraud. Three things can happen:

No objection. The Civil Status Officer registers the declaration and you are Belgian from the date of registration.
No response within four months. The declaration is automatically approved.
Negative opinion. The case moves to the Court of First Instance, where you can contest the decision.

After registration you are notified to apply for a Belgian identity card and passport.

Naturalization by Parliament

Naturalization is a separate procedure handled by the House of Representatives, and since the 2012 reform it is reserved for two narrow groups: people with exceptional merit in science, sports, or socio-cultural fields that would contribute to Belgium’s international reputation, and stateless persons legally resident in Belgium for at least two years. Applicants on exceptional-merit grounds also have to explain why the standard declaration process is virtually impossible for them. The file passes through the Public Prosecutor, the Aliens Office, and State Intelligence before reaching the naturalizations committee. Approved cases must be sanctioned by the King and published in the Belgian Official Journal; nationality takes effect on the publication date.⁶

Very few applications succeed each year. For almost every reader, the declaration under Article 12bis is the route.

Do You Have to Give Up Your Current Citizenship

Belgium has permitted dual nationality since 2007. Becoming Belgian does not require you to renounce another citizenship, and acquiring another citizenship later does not cost you your Belgian one.⁷

Belgium’s position does not bind your country of origin, though. Some countries still require renunciation of previous citizenship when you naturalize, or treat the acquisition of another nationality as an automatic loss. Check the rules on both sides before you file.

Keeping Belgian Nationality Once You Have It

One rule surprises second-generation Belgians living abroad often enough to be worth flagging early. If your future child is born abroad after January 1, 1967, holds another nationality, never has a main residence in Belgium between eighteen and twenty-eight, and does not work abroad for the Belgian government or a Belgian company, they will automatically lose Belgian nationality on their twenty-eighth birthday unless they act. Filing a retention declaration at their Belgian consulate, or obtaining a Belgian passport or identity card before turning twenty-eight, is enough to prevent the loss.⁸

If any doubt applies, the retention declaration is harmless and costs nothing beyond a consulate visit.

1
FPS Finance. Paying for a Nationality Application or Name Change
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FPS Foreign Affairs – Foreign Trade and Development Cooperation. Being Granted Belgian Nationality
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FPS Foreign Affairs – Foreign Trade and Development Cooperation. Being Granted Belgian Nationality Before the Age of 18
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FPS Justice. Declaration of Acquisition – You Are Over 18 Years of Age
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European Migration Network Belgium. Pathways to Citizenship for Third-Country Nationals in Belgium
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The House of Representatives. Special Competences – Naturalizations
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FPS Foreign Affairs – Foreign Trade and Development Cooperation. Nationality
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FPS Foreign Affairs – Foreign Trade and Development Cooperation. Losing, Retaining and Regaining Belgian Citizenship