The three key points to remember:
1. The tax return (Form 100) must be submitted no later than 31 December of the year following the tax year. Even if you are not required to file, doing so may still be beneficial.
2. Many expenses are tax-deductible, from insurance premiums to retirement savings schemes, which can significantly reduce the amount of tax you pay.
3. With the right support, from your insurer for your policies and from a partner such as taxx.lu, which guides you through every step from gathering documents to filing your return, you can approach your first tax declaration with confidence and peace of mind.
Have you recently moved to Luxembourg? Between registering with your local commune, finding a place to live and opening a bank account, tax matters inevitably end up on your to-do list. The good news is that your first tax return is more straightforward than it might seem, and it could even allow you to reclaim any tax you may have overpaid. The income tax return (Form 100 or Form 163) must be submitted no later than 31 December of the year following the tax year. Here is a step-by-step guide to help you approach this process with confidence and peace of mind.
Are you required to file a tax return?
First key point: not everyone is obliged to file.
- Mandatory filing (assessment procedure): applies in certain cases, such as income above thresholds, multiple income sources, or when both spouses earn a salary.
- Voluntary filing: even if not mandatory, filing a tax return (or an annual statement via form 163) often helps regularise withholding tax and potentially claim a refund.
As a resident, you must declare your worldwide income, including earnings from abroad.ger.
Resident vs non-resident: what changes?
Your status affects what you declare and what you can deduct.
- Resident: taxed on worldwide income, with full access to deductions.
- Non-resident: generally taxed only on Luxembourg income, but foreign income still plays a role. By opting for resident-like treatment, you can access the same deductions.
Luxembourg also uses tax classes (1, 1a, 2) which affect taxation. Married couples typically fall under Class 2.
Note: for non-resident married couples, Class 2 must be requested as it is not automatically applied.
Steps for your first tax return
The process can be broken down into five straightforward steps, and an online tool such as our partner taxx.lu can assist you with most of them.
- Gather your documents: Collect all the relevant paperwork in one place, including your salary or pension certificate, tax certificates provided by your insurers, and supporting documents for deductible expenses and special charges. On taxx.lu, the AutoScan document recognition feature reads your supporting documents and pre-fills part of your tax return automatically. You then simply review and confirm the information. Some foreign documents may, however, require manual entry.
- Identify your tax deductions: A standard employment expense allowance of €540 is automatically applied to the taxable salary of employees. In addition, you may be able to deduct insurance premiums, retirement savings contributions, charitable donations and other special expenses. Rather than having to identify each deduction yourself, taxx.lu guides you through the tax reliefs and deductions available to you as you complete your return. Its Opti-Score feature also suggests ways to optimise your tax situation for future tax returns.
- Choose how you would like to file: You have three options: A guided service such as taxx.lu, which supports you throughout the entire process in several languages, the paper tax return (Form 100) or online filing through MyGuichet.lu.
- Submit your tax return on time: The deadline is 31 December of the year following the relevant tax year. For the 2025 tax year, for example, the filing deadline is 31 December 2026. With taxx.lu, your estimated tax result is calculated as you complete the return, and payment is only required when you are ready to submit it.
- Receive your tax assessment notice: Once your return has been processed, the Luxembourg Inland Revenue (ACD) issues your tax assessment notice and determines your final tax position. Depending on the package selected, taxx.lu can also review your assessment notice against the information contained in your tax return and help identify any discrepancies.
What expenses can you deduct?
This is where real tax savings can be made. Several major categories of expenses can be deducted from your taxable income.
- Insurance premiums: Certain insurance policies, including life insurance, personal liability insurance and pension-related protection plans, qualify for tax deductions. We explain the eligible policies and applicable deduction limits in detail in our dedicated article: Insurance premiums that can be deducted when you file your Luxembourg tax return – Foyer
- L’épargne prévoyance-vieillesse (article 111bis LIR): For the 2025 tax year, the maximum deductible amount is €3,200 per person. From the 2026 tax year onwards, this deductible limit increases to €4,500 per person.
- Charitable donations: Donations made to approved charitable organisations are tax-deductible, provided they amount to at least €120 and do not exceed 20% of net income.
Good to know: Foyer solutions
Several Foyer products are designed to help optimise your tax position while providing valuable everyday protection:
- horizon: a retirement savings plan that is tax-deductible within the limits set out under Article 111bis of the Luxembourg Income Tax Law.
- protect4life: a flexible and innovative solution combining life cover and savings, under the framework of Article 111 of the Luxembourg Income Tax Law.
- mozaïk home insurance: designed with newcomers in mind, offering multilingual assistance and flexible cover options. (Please note that only the personal liability component of this insurance remains tax-deductible.)
Our online tax return partner: taxx.lu
Completing your first tax return can feel daunting, particularly if it is not in your native language. Among our trusted partners, the Luxembourg platform taxx.lu supports both residents and cross-border workers throughout the entire process, fully online, with personalised assistance via chat and email in several languages.
According to figures published by the platform, the average tax refund obtained by its customers is €2,352. This is an average figure rather than a guarantee, as both refund amounts and processing times are determined by the Luxembourg Inland Revenue (ACD). taxx.lu also holds a 4.9/5 rating on Google.
To find out more, visit:: https://www.taxx.lu.
Good to know: an exclusive offer for Foyer customers
As a Foyer customer, you benefit from a 30% discount on your online tax return through taxx.lu.
FAQ
When do I have to submit my tax return?
No later than 31 December of the year following the tax year concerned. For income earned in 2025, the filing deadline is 31 December 2026.
Am I required to file a tax return if I am an employee?
Not necessarily. Some situations create a filing obligation, while others do not. Even if you are not required to file, submitting a tax return or an annual tax adjustment request can be beneficial, as it may allow you to regularise the tax withheld at source. If in doubt, contact the Luxembourg Inland Revenue (ACD) or make use of a service such as taxx.lu, which can guide you through the process.
How long does it take to receive my tax assessment notice?
Processing times vary and are determined by the ACD. For this reason, it is advisable to submit your tax return well before the filing deadline.
Can I deduct my insurance premiums?
Yes, certain insurance premiums may be tax-deductible, subject to the conditions and limits laid down by Luxembourg tax legislation. Eligible products may include life insurance, personal liability insurance and certain protection policies. For a detailed overview of eligible contracts and applicable deduction limits, please refer to our dedicated article on tax-deductible insurance premiums.
