This volume builds a conceptual basis for assessment promoting learning in Content and Language Integrated Learning (CLIL) classrooms and proposes practical assessment approaches and activities that CLIL teachers can apply in the classroom. CLIL as an educational context is unique, as language and content learning happen simultaneously. The efficacy of such instruction has been studied extensively, but assessment in CLIL classrooms has drawn much less attention. The present volume aims to fill this gap. Arranged based on different ways that content and language are integrated in CLIL, the chapters in this book together build a solid theoretical basis for assessment promoting learning in CLIL classrooms. The authors discuss how assessment eliciting this integration yields insights into learners abilities, but more importantly, how these insights are used to promote learning. The contributors to the volume together build the understanding of classroom-based assessment as cyclic, of teaching, learning, and assessment as inter-related, and of content and language in CLIL classrooms as a dialectical unity. This volume will spark interest in and discussion of classroom-based assessment in CLIL among CLIL educators and researchers, enable reflection of classroom assessment practices, and foster collaboration between CLIL teachers and researchers. The assessment approaches and activities discussed in the volume, in turn, will help educators understand the scope of applications of assessment and inspire them to adapt these to their own classrooms.