Teaching L2 English in secondary and upper secondary school can be challenging for a number of reasons. Not only are students going through adolesence; they often have varying experiences with L2 English and need support with different parts of it. This book provides a summary of fundamental concepts in the field of L2 teaching and learning. The aim is to stimulate interest in the various aspects and decisions that contribute to being successful and confident teachers of successful and confident learners. The content covers a broad range of essential topics, including Communicative Language Teaching, L2 materials analysis, and language learning psychology as well as the four main language skills, listening, speaking, reading and writing. Each chapter provides an overview of key concepts, issues, and terms related to the respective topic, meant to stimulate curiosity about how L2 teaching and learning can be framed, organized, and accomplished. Teaching English in Secondary School is intended as an introduction to L2 teaching for those new to the field and as a reference book for practicing teachers.