This textbook, "Fundamentals of Geotechnical Engineering and Ground Improvement Techniques," is designed as an introductory course for undergraduate Civil Engineering students and those preparing for competitive exams. It aims to provide a clear understanding of basic concepts and numerical problems in Geotechnical Engineering. The book is divided into two parts. Part I (Chapters 1 to 13) describes the soil properties (index and engineering), methods to estimate the soil properties, estimation of consolidation characteristics, shear strength parameters, estimation of stresses in soils, earth pressure calculations, slope stability analysis, bearing capacity theories and design of pile foundations. Detailed explanations of numerical problems related to each topic are provided to help students prepare for both academic and competitive exams. Additionally, practice problems are included to develop proficiency in problem-solving. Part II (Chapters 14 to 20) covers various ground improvement techniques in practice and the relevant conditions. The topics covered in these chapters are factors to be considered to choose the ground improvement technique, mechanical modification using various compaction equipment, the use of sand drains, prefabricated drains, dewatering techniques, use of different chemical amendments in soil stabilization, thermal methods, grouting techniques, inclusion of various fibers in soil, soil reinforcement, use of various Geosynthetics in ground improvement, Soil nailing, ground anchorage, Gabions, Mattresses, rock bolting, micro piles, diaphragm walls, touch piles, soil liners, ground contamination and remediation of contaminated sites. Any suggestions for improving the content of this book will be gratefully acknowledged and highly appreciated.