In the Netherlands, you are considered as fiscal partners in case you are married or in case you are registered partners. In the year that you get married or register as partners, you can be treated as fiscal partners from the moment that you are registered at the same address in the year of marriage or partnership registration. 

Benefits
As fiscal partners, you can allocate certain joint income items (like principal residence, personal deductions, income from savings and investments) and a partner with no income may be entitled to a tax credit, which can lead to tax benefit. 
 
Fiscal partner tax treatment
If you are not married or registered partners, you can still be tax-treated as fiscal partners if you are registered at the same address and you meet certain conditions. 

Below is a list of the most common situations where you may be treated as fiscal partners:

- you are both 18 years or older, live together and have a notarial cohabitation contract and/or;
- you have a child together and/or;
- one of you has a child, which is formally recognized by the other and/or;
- you are registered as pension-partners with a pension insurance and/or;
- you and your partner own the house in which you both live (and are registered) and/or;
- you were partners in the past year and/or;
- you are both 18 years of age or older and one of you or both of you has a minor child that is also registered at your address.

Apart from the above situations, there are some less common situations in which you can be treated as fiscal partners.


Note that having a rental contract together and/or being partner for immigration purposes does not make you fiscal partners.

Fiscal partners can only have 1 principal residence
If you and your partner both live in your own house and you get married, you are supposed to only have one principal residence from the moment that you get married. So in situations where for example 2 partners live in different cities for the sake of minor children (living close to an ex-partner after divorce) marriage will lead to a different tax treatment of one of the homes - which will then be taxed as an investment.

Note that in situations where one of the properties is for sale and/or if one is being constructed/renovated to be principal residence for both partners in the future, exceptions may apply (former principal residence and future principal residence can temporary lead to more than one principal residence).