Aims <p>Nanofertilizers (NFs) represent an innovative approach to enhance nutrient delivery efficiency and sustainability in modern agriculture. This review aims to consolidate current advances in the synthesis, mechanisms, and applications of NFs while highlighting their multifunctional role in sustainable crop production.</p> Methods <p>Relevant literature was reviewed to evaluate nano-scale fertilizer formulations, including emerging smart NFs and biogenic NFs synthesized through eco-friendly pathways using plants, microbes, and organic extracts. Mechanistic studies addressing nutrient uptake pathways, including root and foliar absorption, were examined to understand nutrient mobilization and plant physiological responses.</p> Results <p>Current studies indicate that NFs may improve nutrient solubility, enable controlled nutrient release, and enhance targeted delivery to plants, potentially reducing nutrient losses and environmental contamination. Experimental evidence from laboratory and greenhouse studies suggests that NFs can enhance nutrient-use efficiency and may reduce eutrophication risks compared with conventional fertilizers. Biogenic and smart NFs further expand sustainable production approaches and support precision nutrient management. However, challenges remain regarding large-scale production, cost-effectiveness, nanoparticle stability, and long-term soil–microbiome interactions.</p> Conclusions <p>This review highlights the potential of NFs as promising tools for sustainable nutrient management while emphasizing existing knowledge gaps and environmental and regulatory considerations. Addressing these challenges through field-scale validation, environmental safety assessment, and economically viable production strategies will be essential for responsible and sustainable adoption of NFs in agriculture.</p>