What is the deadline to declare my taxes?

Quick Answer

On the 1st of March The online tax portal MijnBelastingdienst opens on belastingdienst.nl and you can start your tax declaration. If you have received a letter from the Belastingdienst informing you that you have to file your taxes then you must ensure that your tax declaration arrives at the tax office by May 1st. If you have not received such a letter but you do need to update your information you have until July 14th to do so.