Green nanotechnology is an emerging and sustainable method of producing nanomaterials, and it uses medicinal plants as environmentally friendly “nano factories” to synthesize nanoparticles without the need for hazardous chemicals or excessive energy. Nanotechnology is a new and developing technology with many uses. Materials of one dimension between 1 and 100 nm are synthesized and used in this process. Nowadays, a broad range of physico-chemical techniques is employed to create nanoparticles. However, biogenic reduction of metal precursors to yield matching nanoparticles is more cost-effective, environmentally friendly, and free of chemical impurities for biological and medical applications. One of the green synthesis strategies is to take advantage of the potential of medicinal plants. Since metal nanoparticles have drawn a lot of interest worldwide, we have covered and concentrated on a variety of metallic nanoparticles made by green synthesis with medicinal plants in this work. Plants include secondary metabolites and biomolecules that facilitate the simple reduction of metal ions to nanoparticles. The biological approaches aid in the removal of harmful processing conditions by allowing the synthesis to occur at room temperature, at a biological pH, and at a cost that is both reasonable and affordable. The greatest biological substitutes appear to be medicinal plants and plant extracts. Plants are known as nature’s chemical factories. This approach has several benefits over conventional methods, such as scalability, sustainability, and cost-effectiveness. Nonetheless, issues including plant composition heterogeneity, industrial scaling-up, and thorough toxicity assessments need to be resolved. This strategy might revolutionize the synthesis of nanoparticles while adhering to green chemistry principles by using medicinal plants as natural nanofactories. This would help the development of sustainable practices in nanotechnology and medicine.