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.