<p>Geotechnical, geosynthetics, and geoenvironmental engineering have traditionally focused on ensuring technical performance while also considering cost optimization and construction efficiency; however, broader considerations, such as sustainability and resilience, have often received limited attention. Growing global challenges such as climate change, resource depletion, and environmental pollution require these engineering practices to integrate sustainability and resilience. Although sustainability is increasingly used as a guiding principle in geotechnical, geosynthetics, and geoenvironmental engineering practices, it is often misapplied through <i>greenwashing</i>, where projects are falsely labeled as sustainable without a proper quantitative assessment. To address this challenge and effectively integrate sustainability into geotechnical, geosynthetics, and geoenvironmental engineering practices, it is necessary to objectively select and quantify indicators representing the triple bottom line of sustainability: environmental, social, and economic dimensions. Environmental sustainability assessment tools range from simple carbon footprint calculators to more comprehensive life cycle assessment (<i>LCA</i>). While carbon footprint calculators estimate greenhouse gas (GHG) emissions, <i>LCA</i> evaluates a broader range of environmental impacts beyond just the carbon footprint. Additionally, economic sustainability assessment tools, such as life cycle costing and cost-benefit analysis, can be utilized to quantify the direct and indirect costs and benefits associated with a project. Moreover, although social sustainability indicators are challenging to select and quantify, tools such as the Social Sustainability Evaluation Matrix (<i>SSEM</i>) can help define and quantify these indicators. Integrated sustainability assessment tools, such as <i>QUALICS</i>, apply multi-criteria decision analysis (MCDA) to integrate environmental, economic, and social metrics, thereby supporting informed decision-making in selecting the most sustainable option. Finally, recognizing the growing impacts of climate-induced hazards on geo-systems, integrated resilience and sustainability assessment tools, such as <i>TQUALICSR</i>, are warranted. This study first reviews commonly used sustainability assessment tools and then presents case studies demonstrating their application in evaluating the sustainability of geo-systems, optimizing project components to enhance sustainability, and selecting the most sustainable alternative among multiple solutions for a given engineering problem. The case studies evaluated include geotechnical site investigation methods, field pile load testing methods, deep foundation (pile) design optimization, retaining structure design using geosynthetics, ground improvement methods, landfill design using geosynthetics, coal ash impoundment closure design, and selection of contaminated site remedies. A case study demonstrating the application of an integrated sustainability and resiliency assessment tool, specifically <i>TQUALICSR</i>, for selecting the most sustainable and resilient technology for contaminated site remediation is also presented. Overall, the use of quantitative assessment tools in evaluating the sustainability of geotechnical, geosynthetics, and geoenvironmental engineering projects is becoming increasingly common and valuable in engineering practice. However, relying solely on simplified methods without comprehensive triple-bottom-line sustainability assessments can lead to potentially misleading conclusions. In this context, this study presents both the challenges and the opportunities in advancing quantitative sustainability and resiliency assessment tools to guide the selection of sustainable and resilient geosystems.</p>