This book constitutes the refereed proceedings of the 32nd International Colloquium on Structural Information and Communication Complexity, SIROCCO 2025, held in Delphi, Greece in June 2025.The 24 full papers and 4 brief announcements included in the proceedings were carefully reviewed and selected from a total of 57 submissions. They focus on innovative methodological and solution approaches in structural knowledge, communication, and computing in decentralized systems of multiple comunicating entities.