Conditions under which resident taxpayers become subject to tax obligations in Luxembourg

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In general, resident taxpayers who receive income that is taxable in Luxembourg may be subject to various tax obligations in Luxembourg.

Certain resident taxpayers are required to file an income tax return (known as taxation by assessment).

Other taxpayers can regularise their tax situation by filing a tax return or by applying for an annual adjustment.

All taxpayers are required to declare their income if the Luxembourg Inland Revenue (Administration des contributions directes - ACD) requests them to do so.

Who is concerned?

Any taxpayer can:

  • be ordered to declare their income; or
  • decide on their own to file a tax return; or
  • request an annual adjustment.

by taking into account the income and expenses from 1 January to 31 December of the tax year.

How to proceed

Taxpayers required to file an income tax return

The taxpayer is required to file an income tax return (using form 100), if:

  • the annual taxable income at source in Luxembourg exceeds EUR 100,000; or
  • in case of multiple income streams or pensions taxable at source in Luxembourg, the annual income exceeds EUR 36,000 for tax classes 1 or 2, or exceeds EUR 30,000 for tax class 1A.
    • taxpayers employed concurrently by several employers;
    • pensioners receiving several pensions;
    • married taxpayers taxed and filing jointly, both of whom are employed or receive a pension; or
  • taxpayers whose taxable income in Luxembourg is not subject to tax withholdings, such as:
    • earnings from self-employment;
    • rental property income;
    • wages or salaries paid by a foreign employer, or pensions paid by a foreign pension fund; or
  • taxpayers whose taxable income includes more than EUR 1,500 in net investment income subject to withholding tax, such as dividends;
  • taxpayers whose taxable income includes more than EUR 1,500 in directors’ fees;
  • spouses who are not separated, one of whom is a resident taxpayer and the other a non-resident, who chose to be jointly taxed and who provisionally obtained tax class 2 on their tax card. 

The taxpayer is also required to declare their income if the Luxembourg Inland Revenue (Administration des contributions directes - ACD) so requests.

Taxpayers for whom the filing of an income tax return is optional

Taxpayers for whom the filing of an income tax return (using the form 100) is not compulsory can file a tax return nonetheless if they fall into at least one of the following categories:

  • they wish to deduct the interest expenses on a loan taken out for their main residence or for any other real estate that they built or which is under construction; or
  • they have requested to be taxed jointly with their partner in order to qualify for the class 2 tax rate. The 3 neighboring countries of Luxembourg all recognise formal civil partnerships, namely the "Civil Solidarity Pact" in France, the "Legal Cohabitation Contract" in Belgium and the "Eingetragene Lebenspartnerschaft" in Germany; or
  • spouses who are not separated, one of whom is a resident taxpayer and the other is a non-resident who chose to be taxed jointly in Luxembourg, provided that the resident taxpayer has earned 90 % of the household's income during the tax year.

Annual adjustment procedure

Taxpayers who do not satisfy the conditions for filing an income tax return may, under certain conditions, submit a request for an adjustment of tax withholdings by way of the annual adjustment procedure.

In particular, it is in the interest of taxpayers to file an annual adjustment request when:

  • they begin their professional career in Luxembourg in the course of the year after completing their studies; or
  • they work as temporary workers (interim) and have variable or zero monthly earnings; or
  • they work in Luxembourg for only part of the year (arrival or departure during the year) and their income earned abroad is proportionally lower than that earned in Luxembourg; or
  • they wish to claim deductible expenses, such as:
    • professional expenses (a category including work-related expenses);
    • pensions paid to the divorced spouse, such as maintenance or other support payments;
    • mandatory social security contributions and deductions;
    • insurance contributions and premiums;
    • premiums paid into a private pension plan;
    • payments into a home purchase savings account;
    • contributions for a supplementary pension scheme;
    • gifts or donations, etc.; or
  • they wish to request the single-parent tax credit; or
  • they wish to request a tax reduction in the form of tax relief, etc.

Online services and forms

Who to contact

Luxembourg Inland Revenue

Related procedures and links


Filling in a tax return as a resident (taxation by assessment) Adjustment of withholding tax on salaries by annual adjustment as a resident taxpayer Choosing between joint taxation or individual taxation as a married taxpayer Requesting a tax allowance for extraordinary expenses


Further information

Legal references

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