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CertiDocsThe practical guide

Belgian nationality as the spouse of a Belgian

This declaration requires, among other conditions, five years of legal residence, knowledge of a national language and social integration. The category covers the spouse of a Belgian after three years of living together in Belgium, or the parent/adopter of a Belgian child meeting the statutory age condition. FPS Justice states that proof of social integration also proves language knowledge. Have your municipality check the conditions and supporting documents for your category.

Understand the process
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What is the correct procedure?

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This declaration requires, among other conditions, five years of legal residence, knowledge of a national language and social integration. The category covers the spouse of a Belgian after three years of living together in Belgium, or the parent/adopter of a Belgian child meeting the statutory age condition. FPS Justice states that proof of social integration also proves language knowledge. Have your municipality check the conditions and supporting documents for your category.

Official sourceFPS Justice - Declaration of nationality

Which order avoids rebuilding the file?

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First verify actual eligibility, then gather the civil-status and integration records, obtain any necessary apostille or legalisation for foreign documents, and only after that translate the useful records. Translating before checking the exact category is the dumbest way to create waste.

What amount should you budget?

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As checked on 3 October 2026, FPS Finance lists a standard duty of €1,030. Confirm the amount for your procedure before paying; attribution of nationality to minors is free. Translation and any municipal charges are separate budget items.

Official sourceFPS Finance - Nationality registration duty and payment evidence

Documents to prepare

  • Valid residence permit covering the required legal stay in Belgium
  • Marriage certificate and records proving life together in Belgium during the required period
  • Complete birth certificate and consistent identity records
  • Proof of social integration and, depending on the file, work or training records
  • Check exemptions and accepted languages for the requested records. Apostille or legalisation of the original only if required; sworn translation only if requested, with its formalities checked separately.

Steps to follow

  1. Verify eligibility

    Check the five years of legal stay, the three years of life together in Belgium and the applicable integration route.

  2. Gather the records and proof

    Prepare the marriage certificate, birth certificate, residence permits and proof of social integration.

  3. Authenticate and then translate

    Handle apostille or legalisation of foreign records before the sworn translation of the useful records.

  4. File with the municipality

    Submit a readable and complete file to obtain the receipt that triggers the opinion deadline.

Good to know

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Frequently asked questions

+Is marriage to a Belgian enough on its own?
This declaration requires, among other conditions, five years of legal residence, knowledge of a national language and social integration. The category covers the spouse of a Belgian after three years of living together in Belgium, or the parent/adopter of a Belgian child meeting the statutory age condition. FPS Justice states that proof of social integration also proves language knowledge. Have your municipality check the conditions and supporting documents for your category.
+Why not apply directly for naturalisation?
Because naturalisation is an exceptional favour. For the spouse of a Belgian who meets the ordinary conditions, the correct door is the declaration route.
+Is legal cohabitation enough for this guide?
No. This guide targets the route for the spouse married to a Belgian. Do not assume legal cohabitation automatically triggers the same category.
+When do you become Belgian if the prosecutor does not reply?
FPS Justice states that if no opinion is issued within four months after the receipt, the opinion is deemed positive and the nationality act is drawn up.
+Do foreign documents need translation before filing?
Yes if they are necessary for admissibility and the authority cannot use them directly. But handle apostille or legalisation first where required.

Official source

Official sources used

The references below are the public sources used to document this page. The competent authority always retains the final decision.

Official sourceFPS Justice - Declaration of nationalityOfficial sourceFPS Justice - Devenir belgeOfficial sourceFPS Justice - NaturalisationOfficial sourceFPS Finance - Nationality registration duty and payment evidence

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