This book constitutes the proceedings of the 15th International Conference on Intelligent Tutoring Systems, ITS 2019, held in Kingston, Jamaica, in June 2019.The 14 full papers and 13 short papers presented in this volume were carefully reviewed and selected from 42 submissions. In the back matter of the volume 4 poster papers are included. They deal with the use of advanced computer technologies and interdisciplinary research for enabling, supporting, and enhancing human learning....