Large language models (LLMs) have become central to contemporary advancements in education. LLMs facilitate applications such as automated feedback, question generation, sentiment analysis, and multilingual accessibility. This chapter examines the mechanisms that underpin LLMs—namely, transformer architecture, pre-training, and generative abilities. Moreover, we present the diverse applications of LLMs in education, some of which will be covered in subsequent tutorial chapters in the present book. Lastly, we explore tools for interacting with LLMs, from beginner-friendly web interfaces to more advanced tools like APIs and frameworks such as the OpenAI API and Hugging Face’s Transformers.