The green synthesis of nanoparticles using plant extracts presents a sustainable and versatile approach, with diverse applications across multiple fields. Recent studies in green synthesis have explored a wide range of plant species for synthesising metal nanoparticles, owing to their rich phytochemical content. Plants rich in secondary metabolites, such as Azadirachta indica, Ocimum sanctum, and Camellia sinensis, have been successfully employed in the green synthesis of metal nanoparticles such as silver, zinc oxide, copper oxide, and iron oxide nanoparticles. These nanoparticles are gaining significant attention for applications in antimicrobial treatments, cancer therapy, targeted drug delivery, environmental detoxification, and biosensors. Silver nanoparticles are particularly prominent due to their enhanced efficacy against drug-resistant bacterial strains. This review highlights various plant-based synthesis methods, explores key factors influencing nanoparticle formation, and discusses advancements in green nanotechnology. Special emphasis is placed on recent research publications related to plant-based nanoparticles. The review also outlines the diverse biomedical and environmental applications of plant-based nanoparticles.