This book constitutes the thoroughly refereed post-conference proceedings of the 4th International Conference on Mobile, Secure, and Programmable Networking, held in Paris, France, in June 2018. The 27 papers presented in this volume were carefully reviewed and selected from 52 submissions. They discuss new trends in networking infrastructures, security, services and applications while focusing on virtualization and cloud computing for networks, network programming, software defined networks (SDN) and their security.