Recent research has highlighted an urgent need to support teachers in addressing and meeting the demands of today’s increasingly multilingual classrooms in Europe and even beyond (European Commission, 2017). Considering the current role of English as a lingua franca (ELF), referred to as the most frequently employed means of communication in multilingual and multicultural contexts (Mauranen, 2018; Seidlhofer, 2018), it comes as no surprise that particular emphasis is put on the professional development of English language teachers (ELTs). However, despite being acknowledged, ELF-related issues have not been adequately addressed in most teacher education endeavours across Europe yet (Dewey & Patsko, 2018; Sifakis & Bayyurt, 2018). To this end, the ‘English as a Lingua Franca Practices for Inclusive Multilingual Classrooms (ENRICH)’ Project has set out first to raise what has been termed as “ELF awareness” (Sifakis, 2019; Sifakis & Bayyurt, 2018) of ELTs and also to help them develop competences essential for integrating ELF into their teaching. With the cooperation of five European partner countries (i.e., Greece, Turkey, Italy, Portugal, and Norway), the ENRICH Project has developed and implemented an innovative and sustainable online Continuous Professional Development (CPD) Course, which aims at equipping ELTs with competences required for adapting their teaching practices in view of the role of ELF in the current multilingual classrooms. The ENRICH CPD Course is based on multi-level, cross-country exploration of teachers’ and learners’ needs in today’s multilingual classrooms and is available on the official website of the Project at: http://enrichproject.eu/. This special issue of BUJE brings together a series of papers presented, as either a plenary talk or an oral presentation, in the event entitled “ELF Day 5: ENRICHing Pedagogical Issues and Concerns in ELF Research”. This event, held online on February 27, 2021, was organized by the Boğaziçi University ENRICH project team and dedicated to the ENRICH Project for dissemination purposes. It was indeed the 5th academic event taking place within the context of the ELF-Day seminar series organized by Boğaziçi University Sociolinguistics Research Group in collaboration with the Department of Foreign Language Education.