This book presents the background to the current shift in language education towards action-oriented/action-based teaching, and provides a theorization of the Action-oriented Approach (Ao A). It discusses the concepts and theories that paved the way for the Ao A and explores their relevance for the way language education is conceived and implemented in the classroom. In the process, it revisits the concept of competence and discusses the dynamic notions of mediation and plurilingualism. The authors explain the way in which the Common European Framework of Reference for Languages (CEFR) and its recent update, the CEFR Companion Volume, broaden the scope of language education, in particular in relation to the actional turn. The book provides scholars and practitioners with a research-informed description of the Ao A, explains its implications for curriculum planning, teaching and assessment, and elaborates on its pedagogical implications.