- Countess Joanna Zaria Nicoline Milou of Orange-Nassau, Jonkvrouwe van Amsberg (2005)
- Prince Constantijn of the Netherlands (her paternal uncle)
- Eveline Wisse Smit (a former Dutch hockey player and half sister to her mother)
- Baroness Sophie von der Recke (her father's cousin)
- Emma Bonino (presumably a friend of her parents-she was also a bridesmaid at her parent's wedding)
Due to her parents controversial marriage, she and her sister were primarily raised in London. However, since their father's accident in 2012 and subquent death in 2013, I believe Princess Mabel has returned with her daughters to The Netherlands.