Textbooks are a central tool for designing classroom practice in foreign language education and beyond. They provide teachers with valuable content, help plan, monitor, and evaluate learning processes, and influence teaching methods, objectives, and curricula. Fundamentally, textbooks ought to align with current educational policy requirements, such as the implementation of intercultural education, which is why they are considered a ‘hidden curriculum’ for teachers, especially at lower secondary level. As textbooks determine a large part of contemporary classroom practice, it is vital to examine what kind of student engagement they can promote and trace educators’ decision-making processes regarding their use and adaptation. This chapter uses selected data from a mixed-methods study to show how elements of intercultural education are implemented in an EFL textbook used in lower secondary education in Austria. The chapter also addresses the beliefs, approaches and decision-making processes of four EFL teachers, illustrating the different ways in which teachers use and adapt the material at hand, particularly against the background of intercultural education. The chapter offers implications for practitioners, teacher educators, and materials designers.