The book Functional English Grammar discusses the basic concepts of English grammar using a functional approach, which means understanding grammar not only as a set of rules, but also as a tool for conveying meaning in communication. This book is designed to help readers understand English language structures in a systematic and practical way. The discussion begins with an introduction to grammar and grammatical functions, followed by various tense forms such as present, past, and future. In addition, the book also explores the use of modal verbs, passive voice, relative clauses, as well as gerunds and infinitives that are commonly used in both everyday and academic communication. In the final section, the book covers prepositions and prepositional phrases along with the challenges often faced by English learners. Equipped with examples and practice exercises, this book is expected to serve as an effective guide for students, university learners, and anyone who wants to improve their English grammar skills in a practical and contextual way.