This article contributes to the debate on human rights education in diverse societies. It is concerned with the relationship between participation and the co-construction of national belonging. Our data consists of 289 pupil texts and 33 focus group discussions in 6 upper secondary schools in Norway. The role of the school in nation-building is well-known, often emphasizing policy documents or curricula. However, it is in the interaction between pupils and their teachers that the production and re-production of the nation occurs. Participatory exercises in our focus groups functioned as pedagogical interventions, helping pupils to reflect on how they understand, discuss and co-construct national belonging. We find that the potential for co-construction of national belonging, through pedagogical interventions, depends on who is acknowledged as a legitimate participant. Notwithstanding power hierarchies, it can be argued that group discussions are concrete ways to help young people in diverse classrooms co-construct national belonging.