This book constitutes the refereed proceedings of the Fourth International Conference on Futuristic Trends in Network and Communication Technologies, FTNCT 2021. The prime aim of the conference is to invite researchers from different domains of network and communication technologies to a single platform to showcase their research ideas. The selected papers are organized in topical sections on network and computing technologies; wireless networks and Internet of Things (IoT); futuristic computing technologies; communication technologies, security, and privacy. The volume will serve as a reference resource for researchers and practitioners in academia and industry.