Abstract
A reflective case study approach, including focus interviews, reflective/reflexive journals and analysis of project-based works of 30 pre-service teachers participating in an undergraduate course was employed to investigate the discrepancy between the teachers' constructivist conceptions and the actual practice. The identified discrepancy seemed to be an outcome of the difficulty translating constructivism into teaching practice, but also of the misleading conception of constructivism as a homogeneous philosophy. Through reflective practice, participants were able to deconstruct and reconstruct their theories and practices of teaching in more emancipatory ways addressing issues of education for sustainable development (ESD). This case study helped understand the nature of change process towards teaching and learning for more sustainable futures.