This article examines how the self-determination of pupils with intellectual disabilities is practised in secondary school in Norway and discusses possible challenges connected to this practice. The argumentation builds on the fieldwork of qualitative interviews (N?=?55) and participant observations in schools in Norway (pupils 13-16?years old). The pupils attend a variety of educational settings, including ordinary classes at mainstream schools, the department of special education at mainstream schools and special education schools. The study reveals considerable variations in the pupils' opportunities to practise self-determination. While the self-determination of pupils with intellectual disabilities is rather extensive when it comes to their influence over informal and minor decisions in everyday life at school, it is very limited when it comes to formal and major decisions. Furthermore, the implementation of the pupils' self-determination is primarily spontaneous and seldom anchored in the pupils' Individual Education Plans. Such an implementation practice limits the pupils' opportunities to participate in democratic processes, learning and social interaction.