This special section on geomechanics and geosynthetics began at the end of September 2009 with targeted invitations to selected individuals with recognized expertise in the interdisciplinary fields of geomechanics and geosynthetics. Each submission was peer reviewed in strict accordance with the Journal’s policy. The result is the seven papers that appear in this special section. These seven papers address different uses of geosynthetics with a primary focus on their reinforcement function in geotechnical and transportation applications. These applications include geosynthetic-encased columns, geogrid-soil and geogrid-aggregate interactions in reinforced soil structures and reinforced road bases, embankments over rate-sensitive soils, geosynthetic-reinforced piled embankments, seismic behavior of reinforced soil walls, and load and resistance factor design for internal stability of reinforced soil walls. These papers use a range of modeling approaches in geomechanical analysis, including three-dimensional and two-dimensional finite-element modeling, mechanistic-empirical modeling, discreteelement modeling, and probabilistic methods. The breadth of the geosynthetics applications addressed in this collection and the range of analytical, computational, and validation methods employed by the authors demonstrate their value to improve our understanding of the complex mechanics of geosynthetic-geomaterial systems and to advance analysis and design methods. We hope that the readers of this issue will find this special section to be a valuable collection of papers, especially for those interested in numerical modeling of geosynthetics applications, verification of analytical and probabilistic-based design methods, and researchers developing new constitutive models for soils, aggregates, and geosynthetics. We congratulate and thank all of the authors who contributed to this special section. We would also like to acknowledge the valuable contribution of the anonymous reviewers. Finally, we would like to express our appreciation to Professor Musharraf Zaman, the Editor-in-Chief of the International Journal of Geomechanics, for his support and patience in seeing this special section through to completion.