This book constitutes the refereed post-conference proceedings of the 4th International Symposium on Algorithmic Aspects of Cloud Computing, ALGOCLOUD 2018, held in Helsinki, Finland, in August 2018. The 11 revised full papers were carefully reviewed and selected from 29 submissions. The aim of the symposium is to present research activities and results on topics related to algorithmic, design, and development aspects of modern cloud-based systems.