The last decade has seen a groundswell of developments in educational policy in the UK relating to inclusive education for students with special educational needs (SEN). However, whether government policy has been fully implemented in schools remains a concern. The experience of students with autistic spectrum disorders (ASDs) provides an excellent case in point. An increasing number of such students are now educated in mainstream schools, but the limited research in this area has indicated that their experience of school is often marked by bullying, social isolation and anxiety. In light of this, the aim of the current study was to examine the extent to which inclusive educational policy was actually reflected in the practices of four mainstream secondary schools. An exploratory case study approach was adopted, utilising interviews with pupils, teachers, other school staff (e.g., senior managers, learning support assistants) and parents, observations of lessons and other contexts (e.g., lunch time), and document analysis. Our findings highlighted a number of school practices which acted as facilitators or barriers to students’ learning and participation, some of which were generic to SEN provision, and some of which appeared to be specific to those on the autistic spectrum. A discussion of these is presented to enable further understanding of, and inform practice relating to, the inclusion process for students with ASDs.