The utilization of nanotechnology in agriculture has emerged as a promising avenue for enhancing plant growth and productivity. Chitin, a naturally occurring polysaccharide abundant in the exoskeletons of crustaceans and insects, has gained attention as a sustainable and eco-friendly source for nanoparticle synthesis. This chapter explores the role of chitin-based nanoparticles (CNPs) in promoting plant growth and improving crop yields. CNPs exhibit unique physicochemical properties, including high surface area, biocompatibility, and the ability to encapsulate various bioactive compounds. These characteristics make CNPs ideal candidates for novel agricultural applications. The interaction between CNPs and plants involves complex mechanisms, such as improved nutrient uptake, enhanced stress tolerance, and modulation of plant–microbe interactions. Studies have demonstrated that CNPs can serve as efficient carriers for essential nutrients and growth-promoting substances, delivering them to plant roots in a controlled manner. Furthermore, CNPs have been reported to stimulate plant defence mechanisms, leading to increased resistance against pathogens and environmental stressors. The biodegradability of chitin ensures minimal environmental impact, aligning with the growing demand for sustainable agricultural practices. This chapter reviews recent research on the application of chitin-based nanoparticles in agriculture, emphasizing their potential to revolutionize plant growth promotion strategies. The integration of CNPs into existing agricultural practices holds promise for sustainable and eco-friendly crop management, addressing global challenges such as food security and environmental sustainability. Future research directions and challenges in optimizing the use of CNPs for plant growth promotion are also discussed.