This book constitutes the refereed post-conference proceedings of the 4th EAI International Conference on Sustainable Energy for Smart Cities, SESC 2022, held in Braga, Portugal, in November 2022. The 10 revised full papers were carefully reviewed and selected from 29 submissions. They present multidisciplinary scientific results toward answering complex technological problems of emergent Smart Cities. The subjects related to sustainable energy, framed with the scope of smart cities and addressed along with the SESC 2022 conference, are crucial to guarantee an equilibrium among economic growth and environmental sustainability, as well as to contribute to reducing the impact of climate change.