Gold nanoparticles (AuNPs) emerge as a promising technology for managing plant diseases and mitigating stress due to their unique physicochemical and antimicrobial properties. With a typical size range of 1 to 100 nm, these nanoparticles offer versatile solutions to both biotic and abiotic stresses in agriculture. AuNPs enhance plant resilience by improving stress tolerance, acting as nano-primers, and stimulating plant immune responses. Their antimicrobial activity, which includes mechanisms such as membrane disruption, reactive oxygen species (ROS) generation, and modulation of antioxidant pathways, has proven effective against pathogens like Xanthomonas axonopodis, Fusarium oxysporum, and Alternaria alternata. In addition to combatting biotic stress, AuNPs alleviate abiotic pressures such as drought, salinity, and extreme temperatures by enhancing osmotic regulation, nutrient uptake, and cellular integrity. They also activate plant defense pathways, including systemic acquired resistance (SAR), further strengthening plant resilience. Moreover, AuNPs demonstrate synergistic effects when co-applied with other nanoparticles, amplifying their overall efficacy in promoting plant health and crop productivity. The green synthesis of AuNPs using plant extracts provides a sustainable and scalable production method, aligning with environmentally friendly agricultural practices. However, ensuring the safe and effective application of AuNPs requires addressing potential environmental risks and establishing comprehensive regulatory frameworks. Future research should focus on elucidating the molecular mechanisms of AuNP-plant interactions, validating their efficacy through large-scale field studies, and assessing their long-term safety in agricultural systems. This chapter aims to examine the potential of AuNPs in plant disease management and stress mitigation, focusing on their applications, underlying mechanisms, and future research needs for sustainable agricultural development.