Given the rapid population growth and alarming shift in climatic patterns, there is an increasing demand for food alongside a diminishing per capita land availability. Stochastic fluctuations in the environment have rendered plants vulnerable to both abiotic and biotic stressors, ultimately leading to a decline in productivity. To address crop losses resulting from abiotic stresses or pathogen/pest infestations, various strategies have been implemented. Among these, the application of nanoparticles (NPs) has gained widespread popularity in contemporary agricultural practices. Besides, ongoing research has also highlighted the potential harm that NPs may pose to nontarget organisms and their associated environmental threats. Upon release into the environment, NPs experience a complex interplay involving transformation, aggregation, and subsequent dis-aggregation, which determines their ecotoxicological potential. Leaching of NPs infiltrates the soil, compromising the integrity of the surroundings, polluting adjacent aquatic bodies, and thereby adversely affecting both terrestrial and aquatic ecosystems. These NPs undergo biomagnification within the food chain, consequently posing health threats to primary, secondary, and tertiary consumers. The metal and metal-oxide NPs have also been documented for their ability to alter the natural growth and proliferation of rhizospheric microorganisms. This chapter, therefore, provides a comprehensive overview of the various NPs employed within the realm of agriculture, along with an exploration of their ecotoxicological threats and possible regulatory approaches.