In the international literature, the Netherlands is often considered a role model when it comes to school-based sexuality education. Studies show that the majority of Dutch young people receive some information about sexuality at school. However, the actual quality of sexuality education in Dutch schools has hardly been researched. The aim of this study was to explore the curriculum and approach of ‘sexuality and relationships education’ within Dutch secondary schools. Twenty-three Dutch teachers of different schools were interviewed about the way they approach sexuality and relationships education; which topics they discuss and which topics are difficult to discuss; what differences in theme-related knowledge, skills, and attitude they observe between pupils of different cultural backgrounds, educational levels, ages, and gender. The findings show that there is much variation in teachers’ approach of the theme. Of the several topics that were considered difficult, virginity and menstruation were especially difficult in multicultural classes, and homosexuality was the most difficult topic for all teachers in all classes. Teachers’ experiences also pointed at the special need for more tailored sexuality and relationships education of pupils with a non-Western cultural background, pre-vocational education pupils, older pupils, and boys.