This book constitutes the refereed proceedings of the 19th International Conference on Artificial General Intelligence, AGI 2026, held in San Francisco, CA, USA in July 27–30, 2026.The 60 full papers included in this book were carefully reviewed and selected from 167 submissions.A theme emerges from the accepted papers: Searching for a fundamental structure of AGI, via embodied forms and epistemic foundations. In these proceedings you will find deep explorations into the fundamental structure of organizing information, how old architectural assumptions should be thrown out the window, and an explosion in the diversity of approaches to building generally intelligent systems.