The proeftijd is a trial period written into an employment contract that allows both employer and employee to terminate the relationship immediately, without notice or substantive reason. It gives each party a short window to assess suitability before full dismissal protection applies.
Dutch law caps the maximum length by contract duration. For fixed-term contracts of six months or less, no probation period is permitted at all. For contracts longer than six months but shorter than two years, the maximum is one month. For contracts of two years or more and for indefinite contracts, the maximum is two months. Any clause exceeding these limits is void in full, leaving no probation at all rather than reducing to the legal maximum.
The proeftijd must be agreed in writing and must apply equally to both parties. During the trial period, statutory dismissal bans such as the ban on dismissal during illness do not apply, although terminations made for discriminatory reasons remain unlawful.