This book explores teacher agency within Content and Language Integrated Learning (CLIL), highlighting the roles of identity, emotion, discourse, and power. It demonstrates how teacher agency is shaped in curriculum leadership, course design, scaffolding, translanguaging, and cross-curricular collaboration. Focusing on public elementary schools in Taiwan, the first in Asia to adopt CLIL in compulsory education, this book proposes glocalized frameworks of teacher agency for curriculum and teaching in CLIL based on three qualitative case studies sponsored by the Ministry of Science and Technology, Taiwan (107-2410-H-004-116; 108-2410-H-004-099-MY2; 110-2410-H-004-045). This book is an essential reference for educators, researchers, and leaders involved in designing and implementing CLIL in EFL contexts across Asia.