Abstract
<jats:p>This chapter examines the integration of artificial intelligence (AI), particularly large language models (LLMs), into English language teaching (ELT) lesson planning. Drawing on recent empirical research and theoretical frameworks from the field of AI in education (AIEd), the chapter explores how LLMs can support ELT practitioners across diverse educational contexts, from K-12 settings to higher education and teacher training curriculums. The affordances of AI-assisted lesson planning, including differentiated instruction, time efficiency, and resource generation, are discussed alongside critical challenges such as pedagogical reliability, hallucination risks, ethical concerns, and issues of digital equity. The chapter further offers a practical framework for AI-assisted lesson planning and provides sample prompts and lesson plan templates grounded in current ELT pedagogy. Implications are discussed for classroom teachers, pre-service teacher educators, curriculum designers, and researchers.</jats:p>