Deadline for filing the 2024 tax return in Luxembourg

Don't miss the December 31, 2025 deadline for your 2024 Luxembourg tax return. Discover the risks of filing late and how taxx.lu makes it easy.

Every year, many taxpayers ask themselves the same question: what is the deadline for filing a tax return in Luxembourg?

For the 2024 tax year, there are several important rules to be aware of in order to avoid penalties and not miss out on a potential tax refund.

In this article, we review the official deadline, the consequences of late filing, and best practices for filing your tax return with peace of mind.

What is the deadline for filing the 2024 tax return?

For the 2024 tax year, the Luxembourg tax return must be filed no later than 31 December 2025.

This deadline applies in particular to:

• form 100 tax return (personal income tax return),
• form 163 tax return (for employees and pensioners under certain conditions),
• resident and non-resident taxpayers who are required to file a tax return.

Please note: the deadline refers to the date of receipt by the tax office, not the date of dispatch.

Who is concerned by this deadline?

The 31 December 2025 deadline applies to taxpayers who:

• are required to file a tax return (e.g. multiple sources of income, rental income, foreign income, etc.);
• file a tax return voluntarily in order to benefit from a tax refund through tax deductions (loan interest, insurance, home savings plans, special expenses, extraordinary expenses, etc.).

Even if you are not required to file a tax return, doing so can be financially advantageous.

Why is it important to respect the deadline?

Failing to meet the deadline can have several consequences:

• Risk of a fine
  The tax authorities may impose a late filing penalty.

• Loss of a potential refund
  If the tax return is filed late, the authorities may refuse to process the refund request.

• Estimated assessment
  If no tax return is filed, the tax authorities may issue an estimated tax assessment, which is often unfavourable to the taxpayer.

File your tax return easily with taxx.lu

With taxx.lu, filing your tax return becomes:

• 100% online,
• clear and step-by-step guided,
• tailored to residents and non-residents.

Thanks to automatic checks and integrated explanations, you reduce the risk of errors and optimise your tax situation with ease.