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.