This book constitutes the refereed proceedings of the 10th International Conference on Decision and Game Theory for Security, GameSec 2019,held in Stockholm, Sweden, in October 2019.The 21 full papers presented together with 11 short papers were carefully reviewed and selected from 47 submissions.The papers focus on protection of heterogeneous, large-scale and dynamic cyber-physical systems as well as managing security risks faced by critical infrastructures through rigorous and practically-relevant analytical methods.