This article addresses the role of in-company trainers and vocational school teachers in fostering sustainable development within Germany‘s dual vocational education and training system. While there is limited pedagogical preparation for in-company trainers, vocational school teachers undergo extensive professionalisation. However, integration of sustainability aspects in their curriculum remains minimal. Both learning venues, vocational schools and companies, pose challenges to their teaching and training staff and to their role as change agents for sustainable development. To enhance the effectiveness, structural changes in resource allocation and sustained professional development are imperative in both settings. State-funded programmes and curriculum reforms are suggested to fortify teacher preparation for sustainable development, vital in shaping a responsible and equitable future.