The conceptualisation of mediation in the new CEFR Brian North and Enrica Piccardo The CEFR action-oriented approach presents the user/learner as a social agent mobilizing, combining and extending language and general competences plus strategies through carrying out language activities in the accomplishment of tasks in specific contexts. The CEFR outlines four modes of communication: reception and production (= the traditional four skills), plus interaction and mediation. These modes of communication are articulated into a range of pos- sible language activities for which the CEFR provides descriptors for different proficiency lev- els. However, in contrast to interaction, mediation was not elaborated in 2001, with the limited presentation focusing on informal interpretation and translation, despite hints of deeper impli- cations (Piccardo, 2012). This initial focus was fleshed out in Profile Deutsch (Glaboniat et al., 2005), and taken up as ‘cross-linguistic mediation’ in the curricula of German-speaking countries (e.g. Katelhön and Nied Curcio, 2013; Kolb, 2016) and Greece (e.g. Dendrinos, 2006; Stathopoulou, 2015). At the same time, a concept of cultural mediation emerged (Zarate, 2003; Zarate et al, 2004) in reaction against a linguistic, informational focus. Meanwhile, through socio-constructivist, situated approaches to learning, the Vygotskian concept of medi- ation began to take a key role in education and in language learning, further underpinning the CEFR view of the language user/learner as a social agent. This chapter will introduce the descriptors in the recent update to the CEFR (Council of Eu- rope, 2018, 2020), which are articulated through the three categories of mediating a text, me- diating communication, and mediating concepts. Furthermore, the mediation of texts, concepts and/or of the process of communication across varieties, modalities and languages is not pos- sible without taking into consideration plurilingualism and pluriculturalism. Even more funda- mentally, it is through the mediation of concepts and new knowledge, for oneself and/or others, that all learning takes place. The full potential of the articulation of mediation in the CEFR Companion Volume is seen with the operationalisation of these concepts in descriptors. The chapter will focus on the significance for language education of the new CEFR descriptors for mediation activities and strategies and related aspects such as online interaction, literature and plurilingual/pluricultural competence. Keywords: CEFR, Companion Volume, mediation, action-oriented, descriptors