Nanoparticles are an inspiring group of nanostructured materials with broad-spectrum applications in different fields such as catalysis, antimicrobial treatment, drug delivery, nanomedicine, environmental remediation, electronics, and chemical sensors. Nevertheless, the techniques used for preparation are environmentally unfriendly. Aiming to promote the greener synthesis of nanoparticles, this chapter spotlights plant-mediated eco-friendly and sustainable development of nanoparticles. Naturally occurring plant extracts are enriched with a plethora of various biologically active biomolecules and secondary metabolites, including alkaloids, terpenoids, flavonoids, enzymes, and phenolic substances. These bioactive compounds can catalyze the reduction of metal ions into biogenic nanoparticles in an eco-sustainable single-step biosynthetic process. Additionally, the utilization of plant extracts and their derived compounds circumvents the necessity for capping and stabilizing agents and generates bioactive size and shape-dependent green nanoparticles. Herein, we have made an effort that describes the synthesis of a wide range of metal-based nanoparticles (platinum, gold, zinc oxide, silver, and titanium dioxide nanoparticles) by using plant extract as a green synthesis matrix. In addition, different parts of plants that have widely been utilized for the biosynthesis of these NPs with several sizes and shapes by biological methodologies are briefly described. In conclusion, the greener synthesis approaches are safer and easier to exploit the massive preparation of nanostructured particles.