The 3^rd West Asian Symposium on Optical and Millimeter-wave Wireless Communications (WASOWC2020) is hosted at the Tarbiat Modares University (TMU), Tehran, Iran. It follows the successful previous events held in Isfahan University of Technology (2018) and Shahid Beheshti University (2019). WASOWC2020 aims to bring together researchers from academia and industry to share their latest findings in the field of optical & millimetre-wave wireless communications as part of the 5^th Generation and beyond wireless netwroks. The 3^rd Symposium will also include workshops, invited and keynote speakers. High quality and original technical papers are welcome to be presented at WASOWC2020.