This book comprises select proceedings of the 5th International Conference on Optical and Wireless Technologies (OWT 2021). The contents of this book focus on research carried out in optical communication, optoelectronics, optics, wireless communication, wireless networks, sensors, mobile communications, and antenna and wave propagation. The book also explores the combined use of various optical and wireless technologies in next-generation applications and their latest developments in the applications such as photonics, high-speed communication systems and networks, visible light communication, nanophotonics, and wireless and MIMO systems. This book serves as a reference to scientists, academicians, engineers, and policy-makers interested in the field of optical and wireless technologies.