Can You Claim Belgian Citizenship by Descent?

You can claim Belgian citizenship by descent if at least one of your parents was a Belgian citizen when you were born, but the procedure depends on where you were born and where that parent was born. In some cases citizenship is automatic. In others, a Belgian parent has to sign a declaration at a consulate before your fifth birthday, and missing that deadline usually closes the route.

If You Were Born in Belgium to a Belgian Parent

This is the simplest case. If you were born on Belgian soil and at least one parent held Belgian nationality at the time, you are Belgian from birth.¹ The municipality records nationality as part of the birth registration, and your birth certificate is your proof. The other parent’s nationality does not matter.

If You Were Born Abroad and Your Belgian Parent Was Born in Belgium

You are also Belgian automatically if you were born outside Belgium but your Belgian parent was born in Belgium.¹ Your parent should register your birth at the nearest Belgian consulate to create an official record, but your legal status exists from birth whether or not that step happens right away.

For this rule, “born in Belgium” also includes birth in the Belgian Congo before June 30, 1960, or in Rwanda or Burundi before July 1, 1962.¹ If your parent was born in one of those territories during the colonial period, they count as Belgian-born for this purpose.

If You Were Born Abroad and Your Belgian Parent Was Also Born Abroad

This is where claims most often fail. When both you and your Belgian parent were born outside Belgium, citizenship does not pass automatically. The Belgian parent has to sign a formal declaration of attribution at a Belgian consulate, and it must be done before the child’s fifth birthday.² Only the Belgian parent can sign.

The five-year deadline is hard. Belgian consulates confirm that once a child turns five, all the consulate can do is note that the legal window has closed.³ There is no late filing and no appeal of the missed deadline itself. Families who discover their Belgian ancestry after that point generally cannot use this route, and the child’s remaining options usually involve moving to Belgium and applying for nationality as an adult under a separate procedure.

Claims Through a Belgian Mother Before 1985

Belgian nationality law was not always gender-neutral. Before January 1, 1985, citizenship passed almost exclusively through the father. A child born before that date to a Belgian mother and a non-Belgian father was not automatically Belgian, even if the mother was born in Brussels.¹

The 1984 reform of the Belgian Nationality Code changed that. When it took effect on January 1, 1985, roughly 60,000 children of mixed marriages became Belgian. Whether you were caught by that reform depends on your birth year:

Born before January 1, 1967: you are Belgian if your father was Belgian at the time of your birth, or if you were born outside marriage and the first parent to legally acknowledge you was Belgian.
Born between January 1, 1967 and December 31, 1984: you are Belgian if you met the pre-1967 conditions above, or if you met the post-1985 conditions (Belgian father or mother) as of January 1, 1985.¹

These layers matter because most descent claims run back a generation or two. If your line goes through a grandmother rather than a grandfather, you have to check that each link in the chain was legally recognized under the law in force at the time.

The 28-Year Retention Rule

Getting citizenship is only half the job if you live abroad. Belgian law can automatically strip your nationality on your 28th birthday if you were born outside Belgium and never took a specific step. This surprises people who received citizenship as infants and never revisited it.

You have to file a declaration of retention before turning 28 if all of the following are true:

You were born abroad after January 1, 1967.
You hold at least one other nationality, however you acquired it.
You never had your main residence in Belgium between ages 18 and 28.
You never obtained a Belgian passport or identity card between ages 18 and 28.
You do not work abroad for the Belgian government or for a Belgian company or association established under Belgian law.⁴

The easiest way to avoid the trap is to apply for a Belgian passport or eID before your 28th birthday. Doing so exempts you from the retention declaration.⁵ If you do nothing and meet all the conditions above, your Belgian nationality disappears at 28 with no warning from the government.

Dual Nationality Is Allowed

Since April 28, 2008, Belgium has permitted dual citizenship without restriction. Acquiring U.S. citizenship or any other nationality has no effect on your Belgian status, and no declaration to Belgian authorities is required.⁶ The U.S. also recognizes dual nationality, though it taxes citizens on worldwide income wherever they live, so becoming Belgian does not change your IRS filing obligations. Belgium suspended compulsory military service in the early 1990s and abolished conscription in 1995, so new Belgian citizens face no military obligation.

Documents You Need

A descent claim lives or dies on paperwork. The consulate has to see an unbroken chain of evidence linking you to your Belgian parent, and every document must be in the right format:

Your long-form birth certificate listing both parents by name.
Proof of your parent’s Belgian nationality at the time of your birth, such as a Belgian passport valid on your date of birth or a certificate of Belgian nationality.
Your parents’ marriage certificate, if needed to establish the legal parent-child relationship.
The Belgian parent’s birth certificate, to show where they were born, which determines whether the five-year declaration rule applies.

Any document issued outside Belgium in a language other than Dutch, French, or German must be translated by a sworn translator recognized by the Belgian judicial system. Belgium keeps a National Register for Sworn Translators, searchable through the Just-on-Web platform, listing every authorized translator and their working languages.⁷ Using an unauthorized translator will get your documents rejected.

Apostille for U.S. Documents

American vital records cannot be used in Belgium without an apostille, the authentication stamp under the 1961 Hague Convention. Belgian consulates do not legalize U.S. documents themselves. You have to get the apostille from the Secretary of State’s office in the U.S. state that issued the document.⁸ Fees generally run between $10 and $26 per document, and processing takes anywhere from a few days to several weeks depending on the state. A California birth certificate has to be apostilled in California, not in your current state. This step is often the bottleneck, so plan around it.

Filing at a Belgian Consulate

If you live in the United States, you file your declaration at the Belgian embassy or consulate covering your region, by appointment. The consular officer reviews your originals, checks the file is complete, and collects the fee. The current fee for a nationality declaration is $48.⁹ The consulate then forwards the file to Belgium.

Once the file reaches Belgium, the Public Prosecutor’s Office reviews it against the Nationality Code. The statutory review window is four months. The Prosecutor can approve, refuse, or issue a certificate stating no negative opinion is needed. If four months pass with no response, silence counts as approval and the registrar issues a certificate of nationality. Refusals do happen, usually because of incomplete documentation or gaps in the chain of nationality. The appeal window is short, typically 15 days, and refiling with corrected documents is sometimes more practical than appealing.

After approval, you can apply at the consulate for a Belgian passport ($90 for adults, $42 for minors, with delivery in about two weeks) and an electronic identity card ($24, valid 10 years for adults).¹⁰⁹ Holding a valid passport or eID before you turn 28 also satisfies the retention rule.¹¹

If Belgian Citizenship Was Already Lost

If you or a family member once held Belgian nationality and lost it, reacquisition may be possible. The route depends on how it was lost.

For people who lost citizenship at 28 by missing the retention declaration, a reacquisition declaration can now be signed at a Belgian consulate abroad. This option has been available since July 12, 2018, and no longer requires returning to Belgium.³ The consulate will want proof of your former Belgian nationality, such as an old passport or expired identity card, a recent birth certificate with apostille and sworn translation, and a letter explaining how the nationality was lost.

For every other type of loss, reacquisition generally requires returning to Belgium and establishing legal residence for at least 12 months. Since January 1, 2013, applications based on option or other voluntary routes are no longer open to people who do not legally reside in Belgium.³ Former Belgians outside the EU may need a long-stay D visa for reacquisition purposes to enter and start the process. At the U.S. consulate, a D visa application costs $216.⁹

1
FPS Foreign Affairs. Being Granted Belgian Nationality Before the Age of 18
2
FPS Foreign Affairs. Being Granted Belgian Nationality
3
Embassy of Belgium in the United Kingdom. Nationality
4
FPS Foreign Affairs. Retaining Belgian Nationality
5
Embassy of Belgium in Australia. Nationality
6
Belgian Federal Public Service Justice. Dual Citizenship – You Are Over 18 Years of Age – Adult
7
Just-on-Web. Register as an Expert
8
FPS Foreign Affairs. Legalization of Documents
9
FPS Foreign Affairs. Consular Fees
10
FPS Foreign Affairs. Ordinary, Urgent and Very Urgent Procedures – Tariffs
11
FPS Foreign Affairs. Identity Card for Belgians Living Abroad