In the developed world over the last number o f decades, there has been a movement away from the placement o f young persons with significant special educational needs (SEN) in specialised\ segregated educational settings, replaced by the commitment to their enrolment in local mainstream schools, to be educated with their siblings and neighbourhood peers. This policy, where a student with significant SEN spends his / her official school day in the mainstream classroom, originally termed integration, is now more commonly referred to as inclusion, or inclusive education. For the purposes o f this study, the students are considered as having significant SEN if they have been granted additional teaching support and / or the services o f a Special Needs Assistant (SNA) by the National Council for Special Educational Needs (NCSE). The classroom teacher has been identified as a critical factor in the success o f inclusive education. A teacher’s attitudes towards the inclusive process strongly influences their commitment to this initiative. The study employed a qualitative approach to investigate the attitudes o f Irish primary school teachers working in an inclusive classroom. The researcher examined potential determinants in the formation o f teachers ’ attitudes, beliefs and emotions in relation to working in the inclusive classroom; such as teacher education, working relationship with SNA, rewards and challenges associated with the inclusive classroom, influence o f the wider school community, experience of contact with parent/s o f child with significant SEN and experience o f contact with outside professionals supporting the child. Twelve teachers in Irish primary school inclusive classrooms (N - 12) participated in the study. Data were generated through the use of interviews and teacher-written journals. Although the majority o f teachers held positive views towards the inclusion process, concerns were expressed about lack o f supervised placement in the inclusive classroom during initial teacher education (ITE), the availability o f ongoing teacher education in inclusive practices, working relationship with SNA, time constraints and the balance o f rights between the needs of the child with significant SEN and those o f their class peers. While the vast majority o f participants viewed their school principal as being supportive o f inclusive education, they differentiated between what they considered as administrative support for the policy o f inclusion and personal affirmation by the principal o f the teacher working in the inclusive classroom. The findings have implications for policy makers, teacher educators, professionals in the health services, school support services and school principals. The researcher makes some recommendations to address the identified challenges to the formation o f positive teacher attitudes to inclusive education.