The foliar application of nanofertilizers is emerging as a revolutionary approach in sustainable agriculture, offering a solution to challenges such as declining soil fertility, overuse of chemical fertilizers, and environmental degradation. Nanofertilizers, developed through advanced nanotechnology, enhance nutrient delivery efficiency, reduce losses, and minimize environmental impacts. The foliar application involves directly spraying nutrients onto plant leaves, enabling rapid absorption and utilization while bypassing soil-related nutrient losses. This chapter focuses on the mechanisms underlying nutrient uptake via foliar application of nanofertilizers, emphasizing their potential to improve nutrient use efficiency, mitigate abiotic stresses, and enhance crop productivity. Additionally, it highlights the advantages of foliar nanofertilizer application over traditional methods, including reduced fertilizer usage, improved environmental sustainability, and support for precision agriculture. Challenges related to the formulation, scalability, and field-level adoption are also discussed, offering insights into the future of nanofertilizers as an integral component of sustainable agricultural practices.