Luxembourg

Taxable period

The Luxembourg tax year is the calendar year.

Tax returns

As per the Budget Law 2023, individual income tax returns of a given year should, as of tax year 2022, be filed by 31 December of the following year. The deadline for partners or spouses to submit a joint application for individual taxation is on 31 December as well. The deadline for Luxembourg residents to opt for a 20% flat and final tax over qualifying interest income, when the paying agent is located outside of Luxembourg but in the European Union, is now on 31 December.

The total income of a husband and wife and the non-salary income of minor children forming part of the household are aggregated for purposes of the annual tax computation. Combined assessments are due in principle if the spouses are not separated on the basis of a legal or judicial dispensation. Note that all taxpayers are not obligated/authorised to file an income tax return.

The annual tax return or the annual WHT adjustment form has to be filed before 31 December the year following the year the income is received. 

Payment of tax

Payroll income taxes are withheld by the employer on a monthly basis and may be regularised, depending on the circumstances, through an annual tax return or an annual WHT adjustment (décompte annuel).

The payment of income tax may be executed through instalments at the time the taxpayer files a tax return. These advances must be paid on a quarterly basis and are based on income tax paid in the previous year.

Statute of limitations

Luxembourg tax authorities have up to five years to require the payment of tax or the filing of the tax return. This period may be extended if a deferred payment is granted. The general statute of limitation may be extended to ten years in case of (i) insufficient or incomplete tax return or (ii) failure to file a tax return.