<p>This review explores the green biosynthesis of nanoparticles using plant extracts, emphasizing the underlying mechanisms, recent advancements, challenges, and diverse applications of this sustainable technology. Plant-mediated nanoparticle synthesis presents an eco-friendly and cost-effective alternative to conventional methods that often rely on toxic chemicals and energy-intensive processes. The paper examines major biochemical pathways involved in nanoparticle formation, spotlighting the crucial roles of phytochemicals such as flavonoids and phenolics in reduction, stabilization, and capping processes. Equally, it discusses the impact of factors such as pH, temperature, and metal ion concentration on nanoparticle characteristics. Recent advancements, including the use of novel plant extracts and innovative synthesis strategies, are analyzed, along with comparative studies evaluating the efficiency, yield, and stability of nanoparticles derived from different plant sources. The review further explores the broad applications of plant-based nanoparticles across various fields, including medicine, environmental remediation, and agriculture. Crucial considerations related to toxicity, biocompatibility, and regulatory frameworks are also addressed, emphasizing the importance of safety and standardization for industrial applications. Furthermore, the paper identifies existing hurdles such as scalability, reproducibility, and the need for comprehensive characterization methods, proposing future directions for research. By pointing out the potential of plant-mediated nanoparticle synthesis for sustainable development, this review denotes the need for interdisciplinary collaboration and continued innovation to advance the field.</p>