Significant advancements in geotechnical engineering have been facilitated by the application of nanotechnology. This chapter provides an in-depth analysis of how nanoparticles can profoundly influence the fundamental properties of soil, leading to the mitigation of critical geotechnical hazards such as soil bearing failure, excessive soil settlement, and the modification of fluid and sediment characteristics in crucial applications like CO2 geological sequestration and deep geothermal recovery. This also attributes the transformative benefits to the unique features of nanomaterials, highlighting their high reactivity, selectivity, and versatility. It presents compelling examples demonstrating the remarkable capacity of nanoparticles to alter vital properties, including fluid flow, interfacial tension, viscosity, wettability, and pore size distribution, which are essential elements in a wide range of geotechnical engineering applications. Furthermore, the paper explores the uses and associated mechanisms of different types of engineered nanomaterials for soil remediation, while also discussing the potential environmental implications and the important considerations that must be addressed during these remedial applications. Overall, it provides a comprehensive overview of the specific ways in which nanomaterials can enhance geotechnical engineering practices, with a focus on improving soil strength, reducing settlement, and modifying fluid and sediment properties in critical applications. It also examines the versatility of nanomaterials and offers detailed examples of their ability to alter crucial parameters like fluid flow, wettability, and pore size distribution, which are essential in various geotechnical engineering projects.