Employers withhold wage taxes on a monthly basis from the employment income of the employee. The wage tax is an advance payment on the actual income tax due via the Dutch tax return. Besides your employment income, you might also have other sources of taxable income, such as income from freelance activities or business activities. On the other hand, you might also be entitled to some tax credits or deductions because of your personal circumstances. Interest paid on the mortgage of your house, alimony for your ex-partner, and study expenses may lead to that.
In the beginning of every year, a Dutch tax return form for the previous year becomes available on the website of the Dutch tax authorities. Furthermore, in case you for example own a house, you could request the Dutch tax authorities to issue a preliminary tax assessment, to receive the refund due to interest paid on a monthly basis instead of at once when the Dutch tax return is filed.
The Dutch tax return should be filed before May 1. (i.e. for the 2021 Dutch tax return, the deadline is May 1, 2022).
People who have migrated to the Netherlands during the previous year need to file a so-called M Form. This form is since June 2021 also available on the website of the Dutch tax authorities, whereas previously it was only possible to file this on paper.
Non-resident taxpayers (persons with their main place of residency outside the Netherlands) are required to complete the so-called C Form.
Although the Dutch tax authorities try to make things as easy as possible for you, a basic understanding of the system is still necessary. Because you have been recruited from abroad and your personal circumstances may differ a bit from ordinary Dutch people's circumstances, we advise you to get assistance from a tax advisor with knowledge of international tax issues.