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.