Missed Belgium’s tax-return deadline—or do you still have until October?

Log in to MyMinfin with itsme or an electronic identity card and open “My return” or “Mijn aangifte/Ma déclaration.” Some residents receive a proposal for a simplified return—voorstel van vereenvoudigde aangifte in Dutch and proposition de déclaration simplifiée in French. FPS Finance says no submission is required when that proposal is complete and correct, but the taxpayer remains responsible for checking it.

Pay particular attention if you changed employer, married, legally cohabited, separated, had a child, bought another property or received income from abroad. Belgian pension information is normally pre-filled, FPS Finance says, whereas a foreign pension cannot be inserted automatically and must be added by the taxpayer. Salary slips, childcare and donation certificates, mortgage information and other available documents can be consulted through MyMinfin.

If you file jointly, opening the return is not enough: FPS Finance says both spouses or legally cohabiting partners must log in separately and press “Send.” Afterwards, the status in MyMinfin should explicitly show that the administration received the declaration. A saved draft is not a filed return.

Submit the return through MyMinfin without further delay. FPS Finance warns that late or missing declarations can lead to a fine, a tax increase or an assessment imposed by the administration on the basis of the information it holds. Under that assessment procedure, known as an aanslag van ambtswege or taxation d’office, the taxpayer bears the burden of demonstrating the correct taxable income. The authority says it considers the circumstances of each case, so the possible consequences should not be read as an automatic penalty in every late file.

A request for extra time is reserved for serious reasons or force majeure, such as severe illness or the loss of documents through fire or theft, and normally must reach the administration before the applicable deadline. That route is therefore not a general retrospective extension for someone who simply forgot. Anyone whose case involves illness, a platform failure or another documented obstacle should contact FPS Finance and retain the relevant evidence.

For help, use the contact route shown in MyMinfin or on the FPS Finance website. An accountant can file under a secure digital mandate, while a family member or friend may also act through the citizen tax-return mandate system if both parties sign it electronically. Complex cross-border employment, stock options, foreign property or an uncertain residence status may justify professional advice because the correct treatment depends on facts that a pre-filled return may not capture.

The return documents and official explanations are available online in Dutch, French and German. The language of correspondence is governed by Belgium’s administrative-language rules, not simply by the taxpayer’s preferred language. Residents of Brussels

Place

Brussels

Region where residents have broader options concerning the language of future tax documents.

Why it matters

Region where residents have broader options concerning the language of future tax documents.

About

The City of Brussels is the largest municipality and historical centre of the Brussels-Capital Region, as well as the capital of the French Community of Belgium, the Flemish Region, and Belgium. The City of Brussels is also the administrative centre of the European Union, as it hosts a number of principal EU institutions in its European Quarter.

Official site ↗View source record ↗

English-speaking residents can use the English navigation and explanatory material available on parts of the federal portal, but the legally relevant forms remain tied to the official-language versions. Keep the original term or code beside any translation when asking an accountant or the administration about a field.

People living abroad should not confuse the resident return with Belgium’s non-resident income-tax declaration. FPS Finance says the 2026 non-resident filing service opens from September; affected taxpayers should wait for the dedicated notice and dates rather than use the resident deadline as a proxy. Likewise, moving during the year can alter which procedure applies: for the language of the resident return, the administration uses the situation on 1 January.

Belgium’s growing use of pre-filled data has made routine returns easier, but it has not removed the need for individual verification. The half-million figure recorded before the original July deadline was a snapshot of outstanding online declarations, not a measure of tax evasion and not the total number of Belgian taxpayers. Many other residents had received simplified proposals, filed through officials or accountants, or qualified for the October timetable.

The next milestone is 16 October for eligible specific-income returns. FPS Finance will issue assessment notices between August 2026 and the end of June 2027. Until then, filers should retain their supporting documents, confirm that MyMinfin says “received,” and contact the administration promptly if their filing category or residence status remains unclear.