This chapter explores the integration of green nanotechnology and circular economy (CE) principles in agriculture to enhance sustainability and economic viability. Transitioning from traditional linear models to regenerative systems can address key challenges such as resource scarcity, soil degradation, and greenhouse gas emissions. Green nanotechnology, including nano-fertilizers and nano-sensors, offers innovative solutions for optimizing nutrient delivery, improving crop yields, and reducing environmental footprints. Although initial costs are higher, these technologies yield long-term economic benefits by lowering input costs, increasing productivity, and minimizing waste. A cost-benefit analysis of nano-fertilizers highlights their efficiency in nutrient use and potential for mitigating environmental impacts. This chapter also examines the role of precision farming in resource optimization and waste reduction, along with the influence of global and local policies, such as the European Green Deal, in fostering sustainable agricultural practices. Challenges, including regulatory barriers, high costs, and market acceptance, are discussed, with potential solutions through public-private partnerships and targeted incentives. Ultimately, this chapter underscores the transformative potential of green nanotechnology and CE in shaping a more sustainable and economically viable agricultural future.