This book constitutes the refereed proceedings of the 4th International Conference on Decision and Game Theory for Security, GameSec 2013, held in Fort Worth, TX, USA, in November 2013. The 15 revised full papers presented were carefully reviewed and selected from numerous submissions. The conference focuses on analytical models based on game, information, communication, optimization, decision, and control theories that are applied to diverse security topics. At the same time, the connection between theoretical models and real world security problems are emphasized to establish the important feedback loop between theory and practice. Observing the scarcity of venues for researchers who try to develop a deeper theoretical understanding of the underlying incentive and resource allocation issues in security, we believe that GameSec will fill an important void and serve as a distinguished forum of highest standards for years to come.