The purpose of this study was to explore and understand school-based teacher unionism by conducting an empirical analysis of the views and experiences of stakeholder groups in a Gauteng district. Participants saw the role of teacher unions at school level as being the protection of their members. Principals and SGB members and some SMT members thought school based unions protected teachers from being disciplined. Defending of teachers or members was seen as one of the most important roles of teacher unions. This was seen as important because it will ensure that the rights of teachers are not trampled upon especially by school principals. While school principals recognised the rights of union members to join union and the right of unions to organise in the schools they thought that they were unduly and wrongly defending bad teachers. This article also argues that principals were never adequately trained on how to manage union existence at schools. Most participants thought that the role, responsibility and right of teacher unions at school level could not be overlooked. However they still felt that this was emphasised over the rights of other stakeholder groups in the schools especially the learners. Principal and teacher participants, most notably SADTU members, expressed dissatisfaction with their union and did not seem to think that it plays a constructive role in schools. It is argued in this article that teachers’ unions play a role in schools and that this role is either positive or negative. This article is based on my research of school based teacher unionism in one Gauteng district.