Emerging technology to use nanomaterials in different forms for sustainable and safe pest management and crop protection is rapidly developing. Consequently, nanomaterials can be used as biosensors to diagnose plant diseases, delivery vehicles of plant-incorporated protectants for pest/pathogen control, quick and sensitive pathogen/pest probes, and nanofertilizers to boost plants’ ability to tolerate various stresses and increase crop yield. In addition to the minute size of these nanomaterials, the relevant large surface area grants them high reactivity as pesticides and superiority over classical pesticides. Their nanoformulations enable to optimize the pesticidal reliability by increasing penetration/permeability, stability, and solubility as well as adjusting both their release interval and fast degradation. Therefore, this chapter addresses the importance of applying nanopesticides to expand reliable pest management via environmentally safe and cost-effective uses for crop protection in sustainable farming systems. Yet, such an expansion should go in parallel to their ecotoxicological risk assessment to avoid any unfavorable consequences.