PROFESSIONALISATION OF TEACHERS AND MENTORS IN VOCATIONAL EDUCATION TO REALISE POWERFUL TRANSFORMATIVE LEARNING ENVIRONMENTS FOR A SUSTAINABLE TRANSITION (ProVEST) In past years, European policies increasingly focused on the role of school teachers in ensuring effective vocational education and training (VET) as a driver for change. The Riga-Conclusions and the ET2020 working group on VET have stressed the need for qualitative professionalisation opportunities for teachers and mentors in a changing world. Additionally, the European Green Deal includes the development of a European sustainability competence framework to promote learning on environmental sustainability in the European Union. VET plays an important role in providing individuals with the sustainable skills needed to achieve the European Green Deal. To strengthen competences of both teachers and mentors in vocational learning, ProVEST aims to develop a professional development program for teachers and mentors, bringing together schools and companies at both local and international levels, and in various disciplines, covering innovative learning and teaching technologies. More specifically, the project will stimulate the creation of extended teams where teachers and mentors cross boundaries and work together in different professional VET roles to create powerful transformative learning environments for students in vocational education. ProVEST will test the professional development program of the extended teams, supported by a specific, cross-national masterclass. By continuously evaluating and improving the program during the project, the outcome will be an innovative professionalisation approach that can not only be tailored linguistically, culturally and methodologically to the needs of all stakeholders, but can also foster online socialisation and promote digital skills by making all outcomes and training material accessible via different (social) media platforms and the project website.