This book constitutes the refereed proceedings of the 12th International Conference on Computers and Games, CG 2024, held as a virtual event, during November 25-29, 2024. The 17 full papers included in this book were carefully reviewed and selected from 40 submissions. They are organized in the following topical sections: Chess and its Variants; Go and NoGo; General Approaches for Solving and Playing Games; Nonograms; Social Aspects of Games; and Games with Uncertainty.