This book constitutes the refereed proceedings of the 11th Joint International Conference on Serious Games, JCSG 2025, held in Lucerne, Switzerland, during December 4–5, 2025. The 14 full papers, 5 short papers, 16 other papers included in this book were carefully reviewed and selected from 47 submissions. The conference covers a wide range from artificial intelligence applications in games, educational technologies, healthcare and well-being applications, extended reality implementations, user experience design, accessibility and inclusion considerations, and impact studies measuring learning effectiveness.