Content and language integrated learning (CLIL) is a term used especially in Europe for forms of bilingual education where an additional language, in most cases English, is used as the language of instruction in non‐language school subjects. This chapter outlines the development of CLIL, embedded both in European level policies and in growing awareness of the new orientations to language learning introduced, for example, in language immersion research. Because of its potential to serve as a context for meaningful language use and situated language learning, CLIL has been regarded by EU institutions as an important instrument to foster European citizens’ bi‐ and multilingualism, to be offered alongside regular foreign language teaching for students in mainstream education. This chapter introduces the main strands of CLIL research that have revealed a great deal of the possibilities and challenges that CLIL as an educational approach entails, for both students and teachers. Overall, there has been a shift in emphasis in research from studies orienting to effects of CLIL on language learning outcomes to studies that point towards the need to adopt a truly integrated view on language and content, and to explore the potential that CLIL has in supporting the development of subject literacies.