This book constitutes the refereed proceedings of the 12th International Conference on Entertainment Computing, ICEC 2013, held in Sao Paulo, Brazil, in October 2013. The 13 full papers, 6 short papers, 11 posters presented were carefully reviewed and selected from 75 submissions. In addition to these papers, the program featured 2 demos, 3 workshops, 3 tutorials and 3 art installations, also summarized in this book. The papers cover various topics in the multi-disciplinary field of entertainment computing.