Abstract
This research examines the perceived moral authority and political influence of teacher unions in the context of educational sustainable policy development in South African public schools. This study employs Legitimacy Theory and Power Theory to analyse the South African Democratic Teachers Union (SADTU) as a legitimate representative body and a politically influential entity in shaping educational sustainable policy development. A qualitative research methodology was employed, involving data collection through semi-structured interviews with principals, members of the School Management Team (SMT), representatives of the School Governing Body (SGB), and union officials. The data were analysed through thematic analysis. The findings identify four primary themes: (1) teacher unions as sources of moral authority based on advocacy and historical legitimacy, (2) teacher unions as political actors that shape policy dialogues and decision-making, (3) tensions and conflicts regarding power, accountability, and dominance in educational governance, and (4) opportunities for collaborative and constructive engagement in policy processes. The findings demonstrate that teacher unions play a crucial role in fostering democratic participation and representation in educational contexts. However, notable challenges persist, particularly regarding the balance between moral legitimacy and political power, as well as the need for accountability within governance frameworks. This study enhances the existing literature on educational governance and policy by emphasizing the importance of recognizing teacher unions as dual entities that embody both legitimacy and power within education systems. The recommendation emphasizes the creation of balanced, contextually responsive frameworks that facilitate constructive engagement among teacher unions, policymakers, and school leadership to enhance democratic participation and effective educational governance.