The purpose of this study is to examine how some teachers reason regarding the IDP in upper secondary school for pupils with intellectual disability. The chosen theory of the study is curriculum theory and the chosen method of the study is qualitative content analysis.   Ten teachers from five upper secondary schools for pupils with intellectual disability in Central Sweden, which both used and did not use IDP as tools in teaching for pupils with intellectual disability have been interviewed. To analyze the interviews, both the inductive approach and the deductive approach have been used.   The results of the study shows that the IDP has many functions in teaching pupils with intellectual disability at upper secondary school. There were mostly advantages that emerged in the teachers' reasoning regarding the use of the IDP in the education of pupils with intellectual disability, although there were also some disadvantages. In those categories where it was possible to study the existence of curriculum ideologies, it was primarily the learner centered ideology as well as social efficiency ideology that were most prominent.   Current research on IDP has been discussed as well as curriculum and syllabus and how they relate to IDP and pupils with intellectual disability.