Nanotechnology has emerged as a transformative approach in geo-environmental engineering, offering innovative solutions to pressing environmental issues. This chapter assesses the applications, challenges, and future research directions of nanotechnology in this field, including soil enhancement, stabilization, reinforcement, and remediation, as well as contaminant detection and removal. Despite its potential, several significant obstacles hinder the widespread implementation of nanotechnology in environmental applications. These include limited field applicability, high production costs, complex synthesis processes, and potential risks to environmental and human health. Addressing these challenges is crucial; thus, the chapter emphasizes the need for interdisciplinary research and collaboration to deepen our understanding of nanotechnology's real-world impact on environmental remediation. It highlights the importance of long-term monitoring data for evaluating technology efficacy, optimizing process design, and assessing the environmental fate and effects of nanomaterials. Moreover, the review calls for comprehensive risk assessments, regulatory frameworks, and an analysis of ethical and social implications to ensure the responsible and sustainable use of nanomaterials in environmental engineering. Future research directions include investigating nanomaterial-microbe interactions, conducting field-scale studies, performing cost–benefit analyses of in situ remediation technologies, and exploring the behavior of stabilized nanoparticles in unsaturated media. The review concludes that by addressing these challenges and bridging the gap between research and industry, nanotechnology has the potential to significantly advance environmental engineering practices and drive innovation in soil remediation efforts.