A state-of-the-art review of biomimetic nanoparticle synthesis is presented. The technique’s origin has been traced to the studies, started over 150 years ago, on the hyperaccumulation of certain metals by different species of plants. How the initial intracellular method of nanoparticle synthesis evolved into the now widely used extracellular route has been described. The review then covers the gist of all the studies reported on the biomimetic synthesis of nanoparticles of different metals using extracts of different botanical species (plants). The synthesis mechanism is discussed, and the factors influencing the nanoparticles’ extent, shapes, and sizes are identified.