Nanofertilizers, designed to enhance nutrient delivery and uptake in plants, have garnered increasing attention for their potential to revolutionize agricultural practices. This chapter provides a comprehensive overview of the transformations of nanofertilizers in soil and their subsequent uptake by plants, focusing on chemical, physical, and biological processes. Chemical transformations involve the dissolution of nanofertilizers and subsequent release of nutrient ions, influenced by factors such as pH, soil composition, and organic matter content. Physical transformations encompass changes in nanoparticle size, aggregation, and surface properties, affecting their mobility and availability to plants. Biological transformations mediated by soil microorganisms play a crucial role in nanoparticle stability, biotransformation, and plant-microbe interactions. Understanding the mechanisms of nanofertilizer uptake by plants is essential for optimizing their efficacy and minimizing environmental risks. Nanofertilizers can be taken up by plants through both foliar and root pathways. Foliar uptake involves the direct absorption of nanoparticles through leaf stomata or cuticles, while root uptake occurs through interactions with the rhizosphere, including adsorption, diffusion, and endocytosis processes. Moreover, the chapter discusses the factors influencing nanofertilizer uptake by plants, such as nanoparticle properties (size, shape, surface charge), plant species, growth stage, and environmental conditions. Insights into the fate and behavior of nanofertilizers in soil-plant systems are crucial for sustainable agriculture, ensuring efficient nutrient use, minimizing environmental impacts, and enhancing crop productivity. This chapter integrates current research findings and highlights future research directions to advance our understanding of nanofertilizer transformations and their implications for agricultural sustainability.