Abstract
Teacher unions have typically been analysed through the lens of labour relations and collective bargaining; nonetheless, their impact on the governance of internal school matters in public schools is inadequately theorized. This study aims to investigate the influence of teacher unions, especially dominant unions, on internal school management processes in South African public schools. This study is framed by Anthony Giddens’s Structuration Theory, offering an analytical perspective on the interaction between institutional structures and human agency in school management contexts. A qualitative research methodology was employed, based on data collected from principals, School Management Team (SMT) members, and representatives of the School Governing Body (SGB). Thematic analysis was employed to investigate the impact of union involvement on internal management processes, encompassing decision-making, conflict mediation, communication, and organizational functioning in schools. The results indicate four interconnected themes: (1) teacher unions as mediators of internal school management and organisational coordination, (2) teacher union influence on decision-making and organisational practices, (3) challenges and tensions in teacher union involvement in internal school management, (4) opportunities for strengthening collaborative and effective internal school management in unionised contexts. In contexts with fragile institutional support, unions serve as alternative centres of authority, altering internal management dynamics and leadership roles. Union involvement enhances organisational stability and professional support; however, it also poses challenges to leadership autonomy, accountability, and the effective management of internal school affairs. The metaphor, “when SADTU sneezes, the whole nation catches flu,” is used to illustrate the extensive impact of teacher unions on the management processes within schools. This research enhances the understanding of educational leadership and school management by redefining teacher unions as institutional actors at the system level, whose impact extends to internal organizational practices within schools. This underscores the necessity for balanced management frameworks that acknowledge the dual enabling and constraining effects of union involvement, aiming to enhance leadership effectiveness and foster sustainable school improvement.