This chapter explores the role of nanotechnology in addressing water scarcity challenges and improving irrigation efficiency in agriculture. Water scarcity, exacerbated by climate change, population growth, and intensive agriculture, presents a significant threat to global food security. Agriculture accounts for over 75% of global freshwater withdrawals, necessitating advanced strategies to improve water use efficiency (WUE). Nanotechnology offers promising solutions for precision irrigation and sustainable resource management by enabling real-time, high-resolution monitoring and targeted interventions at the molecular level. NanosensorsNanosensors, employing materials such as graphene, carbon nanotubes (CNTs), quantum dots (QDs), and metal oxides, exhibit superior sensitivity, stability, and rapid response in detecting soil moisture, nutrient status, and plant physiological parameters, thereby facilitating optimized irrigation scheduling. Nanoformulations of agrochemicals enhance nutrient use efficiency through controlled release, while nanocomposites and nano-zeolites improve soil water retention and reduce nutrient leaching. Integration of nanotechnology with Internet of Things (IoT), artificial intelligence (AI), and remote sensing platforms has demonstrated substantial improvements in crop yield, WUE, and soil health across diverse agroecological systems. Additionally, applications such as magnetic nanoparticle-mediated delivery and biofabricated nanoparticles further enhance site-specific resource utilization. However, challenges related to scalability, long-term environmental impacts, and regulatory compliance persist. Ongoing interdisciplinary research is critical for developing safe, cost-effective, and scalable nano-enabled irrigation systems to support climate-resilient, sustainable agriculture.