Nanotechnology has advanced rapidly, leading to the application of different nanoparticles (NPs) in daily life. They have garnered significant attention due to their distinct physicochemical properties and useful applications in several fields. Nonetheless, the rapid advancement and widespread application of nanotechnology may result in the inevitable release of nanoparticles into the environment, potentially causing considerable eco-toxicological impacts. Although numerous studies have examined the toxic effects of nanoparticles on humans and animals, further research is essential to understand the detrimental impacts of nanoparticles on plant life. Plants are directly impacted by toxic substances present in the environment, and they also influence the ecological outcomes of nanoparticles and the exposure levels for higher species. This can lead to unexpected hazardous hazards to human beings. Hence, it is crucial to clarify the correlation between nanoparticles and plants in order to emphasis the ecological consequences of nanotechnology. This chapter offers a comprehensive examination of the phytotoxicity of nanoparticles, emphasizing their absorption, transport, accumulation, toxicological and detoxifying mechanisms, evaluation assays for phytotoxicity, factors influencing toxicity, and the spectrum of detrimental effects on plants.