The plant growth-promoting rhizobacteria (PGPR) encourage development of plant by several processes such as siderophore synthesis, biological nitrogen fixation, phosphate solubilization, quorum sensing (QS) and inhibit the formation of biofilms, produce phytohormones, antifungal activity, generation of volatile organic compounds (VOCs), induce systemic resistance, encourage beneficial plant-microbe symbioses, interfere with the production of pathogen toxins, etc. Also, to enhance the production and growth of crops, modern techniques that incorporate nanotechnology are widely used in agricultural practices. Despite its scientific name, nanotechnology has revolutionized a variety of global sectors. Our everyday lives already frequently involve metal nanoparticles and metal oxide nanoparticles (MPs/MONPs), which are widely utilized in a variety of products and industrial processes. Accordingly, once MNPs/MONPs are purposefully or inadvertently released into the environment, soil has been proposed as the primary sink of these pollutants. Environmental concerns related to disturbances in the soil microbial populations and related ecological processes compounded due to rise in episodes of drastic climate-change related abiotic stresses have been witnessed in the last two decades. The crop plants are now being exposed to two most predominant stresses including the oxidative and heavy metal stress due to an emerging environmental contaminant i.e. nanoparticles of metal/ metal oxide/ non-metal oxides and other forms of dual or multiple element nanomaterials (as most efficient NPs used are of metal origin). PGPRs present in soil and rhizosphere of plants have various interactions with nanoparticles, which exert an influence on the plant’s overall health and development. Through a variety of methods, either by themselves or in conjunction with nanoparticles, PGPRs assist in reducing various stresses that plants encounter. This manuscript summarizes the overall mechanism and effect of PGPRs and nanoparticles on plants.