The intensifying pressures on agriculture, driven by a growing global population and climate change, demand innovative strategies to ensure food security. Biotic stressors, including insects, fungi, bacteria, and weeds, pose significant challenges to crop productivity. This chapter explores the application of nanotechnology as a transformative tool for mitigating biotic stresses in agriculture. Nanoparticles (NPs) offer unique properties, such as enhanced reactivity, controlled release, and targeted delivery, improving pest control efficacy while minimizing environmental impacts. Metal-based, polymeric, and lipid nanoparticles have demonstrated remarkable antimicrobial, antifungal, and pest management capabilities. Furthermore, NPs can activate plant defense mechanisms, including systemic acquired resistance, by modulating phytohormones and reactive oxygen species pathways. Advanced nanoformulations provide prolonged protection and reduce agrochemical dependency, addressing pesticide resistance and environmental contamination. This chapter highlights groundbreaking research and practical applications of NPs in biotic stress management, emphasizing their role in sustainable agriculture. Integrating nanotechnology into crop protection enhances productivity, minimizes ecological risks, and supports the transition to resilient agricultural practices amid global environmental challenges.