It was while she was studying at Leiden University that Princess Margriet met her future husband, Pieter van Vollenhoven. This made him the first member of the Dutch Royal House being a commoner and not of royal or noble origin. He was not given any royal titles as a result of the marriage and is therefore formally addressed as “Mister Van Vollenhoven” or by his professional title as “Professor Van Vollenhoven”.

Their engagement was announced on 10 March 1965, and they were married on 10 January 1967 in The Hague, in the St. James Church. It was decreed that any children from the marriage would be styled HH Prince/Princess of Orange-Nassau, van Vollenhoven, titles that would not be held by their descendants.
The Princess and her husband took up residence in the right wing of Het Loo Palace in Apeldoorn. In 1975 the family moved to their present home, Het Loo, which they had built on the Palace grounds.