The MiLLaT Project (Mediation in Language Learning and Teaching) has been initiated as a response to the most recent innovative developments in the field of language teaching, learning and assessment refined in CEFR/CV (2018). The project aims to reinforce the main methodological message of the CEFR, which implies that the learner is to be viewed as a social, plurilingual and pluricultural language user, whose learning process has to be driven by action and task, and whose assessment is to be guided by their communicative ability in real-life situations. The key position in the action-oriented approach does hold MEDIATION, the notion which constitutes the focus of the present project. The needs analysis conducted prior to the project has demonstrated a considerable need for further exploration of mediation, the importance of collaborative research into the state-of-the-art mediation activities and strategies, and a great demand for educational materials, which could offer practical mediation guidelines for teachers and to assure the development of students’ mediation activities and strategies. In view of this, MiLLaT has been created to raise the teachers’ and learners’ awareness of the mediated and complex nature of language learning, to highlight the importance of incorporating mediation (linguistic, cultural, social and pedagogic) into the curriculum development, and designing teaching materials and courses based on real world communicative needs.