Climate change has intensified abiotic stresses such as drought, salinity, and extreme temperatures, posing severe threats to global agricultural productivity. Green nanotechnology offers innovative, sustainable solutions to enhance plant resilience against these challenges. This chapter explores eco-friendly nanoparticle synthesis methods, focusing on plant- and microbe-mediated approaches that reduce environmental footprints. It further elucidates how nanomaterials improve stress tolerance through enhanced nutrient uptake, modulation of antioxidant defense systems, and regulation of stress-responsive gene expression. Real-world applications are evaluated, including nano-fertilizers, nano-pesticides, and nano-sensors, demonstrating their potential to strengthen fragile agricultural systems. Additionally, the chapter addresses critical concerns regarding nanoparticle toxicity, environmental safety, scalability, and their role in supporting a circular economy. By linking research innovations to practical strategies, this work provides a roadmap for integrating nanotechnology into climate-resilient and sustainable farming practices. Future perspectives highlight the importance of interdisciplinary research and responsible deployment for the next generation of green nano-agriculture.