The Finnish education system recognizes religious plurality by offering education in pupils' own religion or in secular ethics. However, little research has been undertaken on how plurality is addressed in classroom practice. This study investigates how 31 minority religion and secular ethics teachers view the task of supporting and including plurality within their classrooms. The findings of this study show how instruction places high demands on teachers due to religious and cultural diversity, as well as age differences in the classroom. Teachers generally made an effort to take diversity into account by considering the different backgrounds of pupils in instruction and engaging pupils in class. However, teachers frequently took a traditional rather than a modern perspective on plurality in religious instruction by assuming pupils' religious belonging. Confessional elements such as religious family background and religious practice outside school were also commonly seen as vital. Consequently, teachers had at times difficulties in supporting pupils with plural or little religious affiliation. The findings show a need to strengthen the non-confessional character of Finnish religious education so that both modern and traditional plurality among pupils occupy an equal position in the classroom.