Plant hormones are natural compounds in plants. They help control growth, development, and how plants respond to stress. Key plant hormones such as abscisic acid (ABA), ethylene (ETH), auxins (AUX), gibberellins (GAs), cytokinins (CK), and brassinosteroids (BR) are widely studied. They play crucial roles during various stages of plant growth and contribute to adaptation to environmental stress. Recently, nanotechnology has gained attention as an innovative strategy to improve phytohormone efficacy in agricultural applications. Scientists use nanomaterials, such as metal and carbon-based nanoparticles, to improve hormone stability, bioavailability, and targeted delivery to specific plant tissues. These nanomaterials can modulate endogenous hormone dynamics by regulating biosynthesis pathways, transport mechanisms, and signaling networks. They may act directly through controlled release and hormone activity modulation and/or indirectly, for instance, by generating reactive oxygen species that influence plant responses. Additionally, smart nanocarriers that respond to stimuli enable precise hormone delivery with reduced environmental consequences. By enhancing plant resilience to environmental stresses and promoting growth and yield, the synergy between phytohormones and nanotechnology offers substantial benefits. Challenges remain, such as the long-term environmental impact of nanomaterials, the need for standardized protocols, and unclear regulations. This chapter examines the latest research on integrating plant hormones with nanotechnology, highlighting key limitations and proposing directions for future studies. Together, these innovations hold the potential to increase crop yield, reduce chemical inputs, and support climate resilience and global food security through sustainable agricultural systems.