Currently, more than 20% of global agricultural soils are impacted by salinity, with the extent of saline areas continuously expanding due to both natural and anthropogenic activities. To mitigate the adverse effects of salinity stress on crops, innovative approaches, including nanotechnology, have been developed. Among these, nanoparticles (NPs) offer a promising approach to lessen the harmful impacts of salinity stress on crops, presenting opportunities for sustainable agriculture. Due to their unique physicochemical characteristics and nanoscale dimensions, NPs have demonstrated considerable potential in reducing the negative consequences of salinity stress. This chapter delves into the function of metal and metal-oxide nanoparticles in enhancing salinity stress tolerance and adaptation in agricultural crops. It also examines the mechanisms through which metal and metal-oxide NPs contribute to improved salt tolerance. Additionally, the chapter provides a critical assessment of the harmful impacts of NPs on plants and discusses the challenges and concerns associated with their extensive use. A thorough grasp of the advantages and limitations of nanoparticle applications can foster the development of sustainable agricultural practices.