This book constitutes the thoroughly refereed post-conference proceedings of the 8th International Conference on Fundamentals of Software Engineering, FSEN 2019, held in Tehran, Iran, in May 2019.The 14 full papers and 3 short papers presented in this volume were carefully reviewed and selected from 47 submissions. The topics of interest in FSEN span over all aspects of formal methods, especially those related to advancing the application of formal methods in the software industry and promoting their integration with practical engineering techniques. The papers are organized in topical sections on agent based systems, theorem proving, learning, verification, distributed algorithms, and program analysis.