This book constitutes the refereed proceedings of the 14th International Conference on Decision and Game Theory for Security, GameSec 2023, held in Avignon, France, during October 18–20, 2023. The 19 full papers and 4 short papers included in this book were carefully reviewed and selected from 33 submissions. They were organized in topical sections as follows: Mechanism design and imperfect information, Security Games, Learning in security games, Cyber deception, Economics of security, Information and privacy and Short articles.