The Entropy 2026 Conference, the third edition organized by MDPI’s Entropy journal, took place from July 1 to 3, 2026, in Barcelona, Spain. It featured sessions on quantum information, quantum computing, complex systems, statistical physics, thermodynamics, and AI applications, with nearly 20 keynote presentations from leading researchers. Over 200 participants from institutions including the University of Cambridge, Princeton University, and Eindhoven University of Technology attended, presenting more than 100 accepted submissions. The event included poster sessions, networking opportunities, an award ceremony, and a closing banquet, and was described as a wonderful success. Participants were invited to submit papers to a special issue of Entropy with a 20% APC discount or to Physical Sciences Forum proceedings free of charge.