In this collaborative action research project three researchers and six primary teachers in two Greek mainstream schools developed a peer tutoring programme for 130 students, 11 of whom were students with special educational needs and disabilities (SEND). Through exploring new roles for researchers and teachers, the aim of this study was to enhance teachers' capacity to develop peer tutoring programmes and improve students' academic and social skills. Teachers and researchers actively collaborated in the development, delivery and evaluation of the programme through the collection and analysis of a range of qualitative data. Data were collected through focus groups, interviews, observations and diaries. The teachers and researchers learned to collaborate in creating an inclusive environment for all students through on-going and in-service support, and to make shared decisions based on honest dialogue. Both teachers and students considered peer tutoring effective for students with SEND but not for all the students without SEND. This collaborative project positively challenged the teachers' and researchers' thinking, highlighting the fact that the development of any inclusive classroom practice, such as peer tutoring, should incorporate the participants' decisions as a means to resolve the complexities between the theoretical underpinnings of inclusion and its practice.