This book constitutes extended, revised, and selected papers from the 13th International Symposium on Artificial Intelligence supported by the Japanese Society for Artificial Intelligence, JSAI-isAI 2021, held online in November 2021. The 26 full papers were carefully selected from 86 submissions. The papers are organized in the volume according to the following workshops: 15th International Workshop on Juris-Informatics, JURISIN 2021; 18th Workshop on Logic and Engineering of Natural Language Semantics, LENLS 18, 5th International Workshop on SCIentific DOCument Analysis, SCI-DOCA 2021; Workshop on Artificial Affective (Kansei) Intelligence, KANSEI-AI 2021; 5th Workshop on Artificial Intelligence of and for Business, AI-Biz 2021.