Belgium Non-Resident Taxation Guide

Belgian-Source Income Categories

• Belgian real estate (KI/RC — cadastral income): A non-resident owning Belgian real estate is subject to: (a) onroerende voorheffing / précompte immobilier (regional property tax — approximately 1.25–3.97% of the indexed cadastral income, plus provincial and municipal surcharges), and (b) personal income tax on the indexed cadastral income (KI/RC) — the cadastral income is added to the non-resident's taxable income and taxed at progressive rates (25–50%). The cadastral income is the deemed rental value, typically much lower than actual market rent. A non-resident can deduct mortgage interest on Belgian real estate against the KI/RC and actual rental income. If the property is rented out, the actual rental income is taxable if it exceeds the indexed KI by more than 66% — the excess is added to the KI for tax purposes.
• Belgian employment income: A non-resident working in Belgium (even temporarily) is subject to bedrijfsvoorheffing / précompte professionnel (wage tax withholding) on the portion of salary attributable to Belgian working days. The employer must withhold wage tax from the first day of work in Belgium, regardless of the employee's residence. Under most Belgian tax treaties, the 183-day rule applies: if the employee is present in Belgium for fewer than 183 days in a 12-month period and the employer is not a Belgian resident, the employment income is taxable only in the home country. Belgian social security (RSZ/ONSS) applies from day one for employees working in Belgium.
• Directors' fees (bestuurdersvergoedingen): A non-resident serving as a director (bestuurder / administrateur) of a Belgian company is subject to Belgian tax on the directors' fees. The fees are Belgian-source income because they derive from a mandate exercised in/for a Belgian company. The tax rate is the progressive personal income tax rate (25–50%). The company must withhold 30% withholding tax (roerende voorheffing) at source, which is creditable against the final personal income tax.
• Belgian pensions: Belgian state, occupational, and private pensions paid to a non-resident are taxable in Belgium (under Belgian domestic law). Most Belgian tax treaties allocate the taxing right to the country of residence — but Belgium retains the right to tax pensions paid by the Belgian state (the "overheidspensioen" / "pension publique" — under the treaty reservation for public service pensions). The pension income is subject to progressive rates (25–50%) with the basic personal allowance prorated to the Belgian-source income.
• Dividends and interest (30% WHT): Belgian-source dividends and interest paid to a non-resident are subject to 30% roerende voorheffing / précompte mobilier (final withholding tax). The rate may be reduced under an applicable tax treaty (typically 15% for dividends and 0–10% for interest). The financial institution or company pays this to the Belgian tax authorities at source — the non-resident does not need to file a Belgian tax return for this income (the withholding tax is the final tax). The non-resident can claim a treaty refund by filing a "bezwaarschrift" / "réclamation" with the FOD Financiën within 3 years of the tax year.

Non-Resident Tax Return (B-Form / Aangifte Niet-Inwoners)

• Who must file: Non-residents with Belgian-source income that is NOT subject to final withholding tax must file a Belgian non-resident tax return. This includes: Belgian employment income (not fully covered by the 183-day exemption), Belgian real estate (cadastral income), directors' fees, Belgian business income through a permanent establishment, and Belgian pensions. The form is the "B" form (aangifte niet-inwoners / déclaration non-résidents). The return is filed electronically via Tax-on-web / Belcotax-on-web or on paper.
• Tax representative requirement: A non-resident without a permanent establishment in Belgium must appoint a tax representative (fiscaal vertegenwoordiger / représentant fiscal) — typically a Belgian chartered accountant or tax lawyer — to file the return and handle correspondence. The representative is jointly liable for the tax due. The representative appointment form (the "machtiging" / "procuration") must be filed with the FOD Financiën before the first return.
• Partial-year residence: An individual who moves into or out of Belgium during the year must file two returns — one as a resident for the period of Belgian residence and one as a non-resident for the remainder. The split is based on the date of arrival/departure at the municipality (the BRP/registre de la population). The personal allowances (belastingvrije som / quotité exonérée) are prorated to the period of residence.
• Deadline: The non-resident tax return deadline is the same as for residents: typically 30 June of the following year (for personal income tax). Paper returns must be filed by 30 June; electronic returns via Tax-on-web by 15 July. Late filing penalties: 10–50% surcharge.

Frontier Workers (Grensarbeiders / Travailleurs Frontaliers)

• France-Belgium frontier workers: Under the BE-FR tax treaty, a French resident working in Belgium is taxable in France (the home country) if the employee works in Belgium fewer than 183 days per year. If the employee works more than 183 days in Belgium, the income is taxable in Belgium. Social security: under EU Regulation 883/2004 and the specific frontier worker agreement, the French frontier worker is subject to French social security (the home country rule for telework facilitation) — as long as the employee does not work more than 50% of the time from France during the COVID-era telework arrangement extension.
• Netherlands-Belgium frontier workers: Under the BE-NL tax treaty, a Dutch resident working in Belgium is taxable in the Netherlands (the home country) if the employee lives within the frontier zone (the border region — typically within 30 km of the border). The employer must still withhold Belgian wage tax, but the employee can claim a tax credit in the Netherlands (the "verrekening" / "compensation" method). Social security: the employee is subject to Dutch social security (the home country rule).
• Germany-Belgium frontier workers: Under the BE-DE tax treaty, a German resident working in Belgium is taxable in Germany (the home country) if the employee works in Belgium fewer than 183 days in a calendar year. The employer must withhold Belgian wage tax; the employee claims a credit in Germany for the Belgian tax paid. Social security: under EU Regulation 883/2004, the German frontier worker is subject to German social security.
• Luxembourg-Belgium frontier workers: Under the BE-LU tax treaty, a Luxembourg resident working in Belgium is taxable in Luxembourg (the home country) if the employee works in Belgium fewer than 183 days. Luxembourg frontier workers are subject to Luxembourg social security. This is the most common frontier worker route — thousands of Belgian residents work in Luxembourg City.

CRS and Cross-Border Reporting

• CRS automatic exchange: Belgian banks, insurers, and investment firms automatically report non-resident accounts to the FOD Financiën / SPF Finances under the Common Reporting Standard. The reported data includes account balance, interest, dividends, and gross proceeds from sales. The FOD Financiën exchanges this data with the account holder's country of residence. For example: a French resident with a Belgian bank account at KBC or BNP Paribas Fortis will have that account reported to the French tax authorities automatically.
• DAC2 and FATCA: Belgium also exchanges data under DAC2 (EU Directive on Administrative Cooperation) and the FATCA IGA (for US persons). Under FATCA, Belgian financial institutions report US account holders to the FOD Financiën, which exchanges the data with the US IRS.

For the full cross-border employment rules and treaty relief, see our Cross-Border Tax Guide →. For the non-resident real estate taxation, see our Property Tax Guide →. For CRS and FATCA reporting, see the FOD Financiën CRS portal.