This book constitutes the refereed post proceedings of the 18th International Conference on Advances in Computer Games, ACG 2023, held online, during November 28–30, 2023.The 14 full papers included in this book were carefully reviewed and selected from 29 submissions. They were organized in topical sections as follows: Chess and its Variants, Solving Games, Board Games, Card Games, Player Investigation, Math, Games, and Puzzles.