To become a Belgian citizen, most adults use a declaration procedure after five or ten years of legal residency in Belgium, meeting conditions on language, social integration, and economic participation. A separate marriage route opens after three years of cohabitation with a Belgian spouse. Naturalization by the House of Representatives exists for people with exceptional merit, but it is rare. Belgium permits dual citizenship, so you generally do not need to give up your current nationality on the Belgian side — though your home country may take a different view.1FPS Foreign Affairs. Losing, Retaining and Regaining Belgian Citizenship
Check with your country’s embassy before applying. Belgium’s rules only govern the Belgian side; some countries automatically strip nationality when a citizen acquires another.
The Five-Year Declaration
This is the most common path. You must be at least 18, hold an unlimited residence permit at the moment you apply, and have five years of continuous legal residency in Belgium. On top of that, three substantive conditions apply.2Belgian Federal Public Service. Declaration of Acquisition
Language. You need to show A2-level knowledge (Common European Framework) of French, Dutch, or German. Proof can be a diploma from an institution recognized by one of the Communities, a certificate from a recognized integration course, or a result from an official exam such as those run by the Alliance Française or Goethe Institut.
Social integration. You can satisfy this with an upper-secondary or higher diploma from a recognized Belgian institution, completion of at least 400 hours of recognized vocational training, or five continuous years of employment.
Economic participation. Salaried workers need at least 468 days of employment during the preceding five years. Self-employed applicants need social security contributions covering at least six quarters in the same period.
These conditions overlap. Five continuous years of work can, on its own, satisfy both social integration and economic participation.
The Ten-Year Declaration
If you have lived legally in Belgium for ten years, you can also apply through a declaration.2Belgian Federal Public Service. Declaration of Acquisition Language knowledge and evidence of participation in Belgian society are still required, but the longer residency gives you more flexibility in how you show integration.
Marriage to a Belgian Citizen
If you are married to a Belgian and have lived together in Belgium for at least three years, you can apply through a declaration without the five-year residency threshold. Language and social integration still apply. Time spent living together outside Belgium does not count.
Exemptions for Older Applicants and People With Disabilities
Applicants aged 65 or older, and applicants with a recognized disability, may be exempt from the language and economic participation requirements. Raise the exemption when you submit at the commune, and bring medical or administrative documentation to support it.
Citizenship for Children Under 18
Minors cannot apply for themselves. A parent or adopting party files a “declaration of attribution” on their behalf.3Belgian Federal Public Service. Declaration of Attribution The rules depend on the situation:
- Child born abroad to a Belgian parent: if the Belgian parent was born in Belgium, the child typically acquires Belgian nationality automatically. If the Belgian parent was also born abroad, the declaration must be filed within five years of the child’s birth at the commune or Belgian consulate.4FPS Foreign Affairs. Being Granted Belgian Nationality Before the Age of 18
- Adopted child: the Belgian adopting party files within five years of the adoption taking effect, while the child is still under 18.
- Child born in Belgium to non-Belgian parents: a child under 12 born in Belgium and resident there since birth may qualify if both parents have had their main residence in Belgium for at least ten years and at least one parent holds an unlimited residence permit.
The declaration of attribution itself is free. Translation and legalization of foreign documents can add costs.
Naturalization by the Chamber of Representatives
Naturalization is not a right but a favor granted by the House of Representatives to individuals who have made exceptional contributions to Belgium in scientific, sporting, or socio-cultural fields.5City of Brussels. Belgian Nationality The application goes directly to the Chamber, not through the commune, and you must explain why the standard declaration procedure is effectively impossible for you and document the exceptional contribution. If you qualify for a declaration, apply there instead.
Stateless persons who have lived legally in Belgium for at least two years can also apply through naturalization without showing exceptional merit. They must be at least 18 and have kept legal residency throughout that period.6Belgian House of Representatives. Special Competences: Naturalizations
How the Application Works
For adult declarations, you submit at the commune where you are registered.7Fedasil. Obtaining Belgian Nationality Assemble the file before you go. An incomplete file stalls everything.
Documents to Prepare
Communes vary slightly, but expect to provide:
- A birth certificate, translated into the language of the region (French, Dutch, or German) by a sworn translator
- Proof of legal residency covering the required five or ten years
- A copy of your current unlimited residence permit
- A language certificate at A2 level or equivalent proof
- Evidence of social integration (diploma, training certificate, or employment records)
- Proof of economic participation (employment attestation or social security contribution statements)
Documents issued outside Belgium must be legalized. If the country signed the 1961 Hague Convention, a single apostille from the competent authority in that country is enough. If the country is not a Hague signatory, you need full diplomatic legalization through the embassy chain, which can take weeks.
Fees
The registration fee for a citizenship application rose sharply in 2025, from €150 to a base of €1,000, under a programme law adopted in July 2025.8EMN Belgium. Acquisition of Belgian Nationality Will Cost €1,000 in Registration Fees The amount is indexed each year to keep pace with inflation. As of January 2026, the indexed fee is €1,030. It is paid at submission and is not refunded if the application is refused.
Timeline
Once you submit, the commune checks the file for completeness and, within 30 working days, forwards it to the Public Prosecutor’s Office, the Immigration Office, and State Security for review.7Fedasil. Obtaining Belgian Nationality The Public Prosecutor has four months from receiving the file to issue an opinion. Silence at the end of that window counts as favorable, and the application proceeds. From submission to outcome, plan for roughly five months, longer if documents are missing or additional investigation is needed.
If Your Application Is Refused
The Public Prosecutor can issue a negative opinion where conditions are not met, whether a gap in residency, thin employment evidence, or security concerns. You receive a written notification with the grounds. You can challenge a refusal before the Court of First Instance, though appeals take time. The stronger defense is a clean file at submission. Common pitfalls include short gaps in residency registration, incomplete employment documentation, and language certificates that do not clearly state the CEFR level.
What Belgian Citizenship Gives You, and One Duty That Surprises New Citizens
As a Belgian citizen, you can live and work anywhere in the EU without a visa or work permit, vote in Belgian federal and regional elections, use Belgian consular protection worldwide, and pass Belgian nationality to your children. You also receive a Belgian passport.
The duty that catches people off guard: voting in Belgium is compulsory.9European Union. Belgium – How to Vote You are legally required to appear at your assigned polling station for federal, regional, and European elections. Voting blank is allowed; showing up is not optional. Non-voters technically face fines of €40 to €80, though enforcement has been minimal in recent years.