Over the course of the last 30 years, inclusive education has emerged as a key aim of education policies around the world. Also in Europe, most countries took efforts to make their education systems more inclusive—which led to growing numbers of children and young persons with disabilities in general education in Europe. The implementation processes of the United Nations Convention on the Rights of Persons with Disabilities (UNCRPD) fuelled these efforts. However, as some authors have argued, not all students with disabilities seem to have benefited in the same way from these developments—such as children and young persons with intellectual disability (ID). This paper aims to explore this phenomenon in more depth by comparing some measures in relation to the implementation processes of the UNCRPD of seven European countries. Doing so, we analyze trends in placements (mainstream and special schools) of students with Special Educational Needs (SEN) in general and of students with intellectual disability specifically. As we show, an increase of students identified as having SEN in mainstream schools can be observed in all countries during the implementation process of the UNCRPD. However, in comparison to this rather broad group of learners, the percentage of students with intellectual disability in mainstream settings did not increase as much. Furthermore, the calculation of the “exclusion rate” revealed that this group of learners remains a key population of special schools. These results need to be understood as effects of specific shortcomings in the implementation of the UNCRPD, as we discuss in a further section. We conclude our paper with recommendations on future research and policies on inclusive education regarding students with intellectual disability.