Nanomaterials have emerged as promising alternatives to conventional materials to enhance the crop protection and sustainability through novel approaches. The unique physicochemical properties of nanoparticles provided applications for targeted delivery and reduced environmental pollution. This chapter explores the application of various nanomaterials including metal-based nanoparticles, carbon-based nanomaterials and polymeric nanoparticles in managing plant diseases. These nanoparticles have proved their ability to deliver agrochemicals to improve plant defence mechanism. Additionally, the ability of nanomaterials in enhancing plant immunity and growth is discussed. Further, the challenges related to toxicity, environmental impact and regulatory considerations of nanoparticles have been discussed extensively. This chapter also concluded further research to optimize nanomaterial-based strategies and to establish guidelines for their responsible use in agriculture.