Sustainable development (SD) topic areas are not directly mentioned in the guiding documents of European language education. Even though language textbooks vary in the number of topics and exercises that promote Sustainable Development Goals (SDGs), there is a need to adapt the textbook content and supplementary materials to integrate sustainability content for language teaching. Our research project, Ethical and Sustainable Language Teaching (EKKO), examined the role of SD in language teaching and discussed how to promote SD by developing engaging language learning activities. Based on existing research literature on Education for Sustainable Development (ESD) and the Transformative Language Teaching for Sustainability model, we developed SDG-related language teaching materials and activities for two language courses (Finnish and German as foreign languages) in higher education to integrate sustainability topics into language teaching. This chapter presents the case materials and analyses the students’ (N = 17) reflections and perceived outcomes. The results show that combining SDG-related topics with ESD methods supported students’ language learning processes and increased their awareness of SDGs. We discuss how language teachers can implement SDGs by adapting the content of language textbooks and developing supplementary materials.