Silver (Ag) nanoparticles are among the most desirable nanomaterials for a variety of applications, such as lithium-ion battery, water pollution monitoring, photocatalytic water splitting, and medical devices. Their increased production and integration in environmental applications play an important role for nanoscience and nanotechnology in engineering. The synthesis methods of Ag nanoparticles include physical, chemical, and biological routes. In this study, we reported a rapid, eco-friendly, and cost-efficient method to synthesize Ag nanoparticles using an extract of banana peel waste as a reducing and capping agent under microwave radiation. A comparison between the conventional heating method and microwave radiation revealed that the microwave radiation method for the extraction of banana peel waste and the synthesis of Ag nanoparticles required much shorter extraction and reaction times. The effects of extraction conditions (banana peel content and extraction time) and synthesis conditions (silver nitrate concentration and reaction time) on Ag nanoparticles were investigated. The optimum conditions were found to be for the extraction: 50 g/L banana peel-to-water ratio and microwave extraction time of 140 s at 800 W and for the Ag nanoparticles synthesis: microwave reaction time of 120 s at 800 W and 1 mM silver nitrate solution and. Plasmonic Ag nanoparticles with a surface plasmon resonance peak at 420 nm and an average size of about 149 nm were synthesized.