This book constitutes the refereed proceedings of the 13th International Conference on Interactive Digital Storytelling, ICIDS 2020, held in Bournemouth, UK, in November 2020. The 15 full papers and 8 short papers presented together with 5 posters, were carefully reviewed and selected from 70 submissions. The conference offers topics in game narrative and interactive storytelling, including the theoretical, technological, and applied design practices, narrative systems, storytelling technology, and humanities-inspired theoretical inquiry, empirical research and artistic expression.