This book constitutes the refereed proceedings of the 15th International Workshop on Enterprise and Organizational Modeling and Simulation, EOMAS 2019, held in Rome, Italy, in June 2019. The main focus of EOMAS is on the role, importance, and application of modeling and simulation within the extended organizational and enterprise context. The 12 full papers presented in this volume were carefully reviewed and selected from 25 submissions. They were organized in topical sections on conceptual modeling, enterprise engineering, and formal methods.