Content and Language Integrated Learning (CLIL) is an educational approach that combines the teaching of subject content with language learning. Originally developed in Europe, CLIL has since been adopted across diverse educational and geographical contexts. This Element offers a comprehensive overview of CLIL, tracing its origins and global development. It examines the theoretical foundations of the approach, as well as key implementation strategies and their impact on language acquisition, content understanding, learner motivation, and attitudes. Special attention is given to how CLIL addresses diversity in the classroom. The text also explores innovative pedagogical practices, such as translanguaging and multimodality, that promote deeper learning and student engagement. It concludes with a discussion on assessment and teacher education within CLIL contexts and outlines the steps needed for its continued growth. This title is also available as Open Access on Cambridge Core.