Amidst changing sociocultural and political climates, limited economic resources and shifting educational policies, classroom teachers continue to hold a significant responsibility in educating an increasingly diverse student population. Balancing the requirement to support student variability within perceived everchanging contexts can be challenging for many teachers. To alleviate some of the pressures in educating diverse student populations, Special Needs Assistants (SNAs) have been deployed to support teachers in meeting the care needs of some children with special educational needs, arising from a diagnosed disability. Grounded in Bronfenbrenner's Ecological System's Theory (1974), the following study explored the interpersonal relationship of teachers and SNAs working in mainstream primary classrooms, in Ireland. Data from quantitative questionnaires and qualitative semi-structured interviews were collected with results from the questionnaires (N = 112) informing the questions for the semi-structured interviews (N = 8). Open-ended questions were used throughout the interview process to collect the nuanced experiences of classroom collaborations from both teachers and SNAs. Findings indicate that SNAs are a well-established and welcomed part of the school workforce. Difficulties with role confusion, a lack of structural guidance around SNA deployment and professional self-efficacy in SEN confirmed the existence of challenges, experienced by the two workforces, which lead to implications in practice for effectively collaborating in classrooms.