This thesis presents a qualitative investigation into the complexities associated with the management of Teaching Assistants (TAs) in mainstream English primary schools. The aim of this study was to determine the specific influence of TAs on the process of social inclusion, with particular regard to pupils identified with Special Educational Needs (SEN). In providing a background for the investigation, three interconnected literature bases are analysed: first, the complexity of TAs’ role; second, the management structures currently operating regarding TAs’ role; and third, the social inclusion of pupils identified with SEN. The methodological approach undertaken was that of the multiple case study, involving three primary schools across England. Semi-structured interviews with the schools’ professionals, a photography method with pupils and non-participant observations were undertaken as data collection methods. Analysis of the data has led to the ‘fuzzy generalisation’ (Bassey, 1998) that TAs’ particular influence over the process of social inclusion in mainstream primary schools lies in supporting pupils with building their social competence to form positive social relationships. A recommendation is made that educational policy considers TAs’ positive influence over the process of social inclusion and thus reconceptualises TAs’ current role to take account of this.