The current agricultural sector is not only in its most vulnerable state but is also becoming a threat to our environment due to expanding population and growing food demands along with worsening climatic conditions. In addition, numerous agrochemicals presently being used as fertilizers and pesticides have low efficiency and high toxicity. However, the rapid growth of nanotechnology has shown great promise to tackle these issues replacing conventional agriculture industries. Since the last decade, nanomaterials especially metal oxide nanoparticles (MONPs) have been attractive for improving agricultural outcomes due to their large surface area, higher chemical/thermal stability and tunable unique physicochemical characteristics. Further, to achieve sustainability, researchers have been extensively working on ecological and cost-effective biological approaches to synthesize MONPs. Hereby, we have elaborated on recent successful biosynthesis methods using various plants/microbes. Furthermore, we have elucidated different mechanisms for the interaction of MONPs with plants, including their uptake/translocation/internalization, photosynthesis, antioxidant activity, and gene alteration, which could revolutionize crop productivity/yield through increased nutrient amount, photosynthesis rate, antioxidative enzyme level, and gene upregulations. Besides, we have briefly discussed about functionalization of MONPs and their application in agricultural-waste-management. We have further illuminated recent developments of various MONPs (Fe2O3/ZnO/CuO/Al2O3/TiO2/MnO2) as nanofertilizers, nanopesticides and antimicrobial agents and their implications for enhanced plant growth and pest/disease management. Moreover, the potential use of MONPs as nanobiosensors for detecting nutrients/pathogens/toxins and safeguarding plant/soil health is also illuminated. Overall, this review attempts to provide a clear insight into the latest advances in biosynthesized MONPs for sustainable crop production, protection and management and their scope in the upcoming future of eco-friendly agricultural nanotechnology.