This book constitutes the proceedings of the Third International Conference on Blockchain, ICBC 2020, held as part of SCF 2020, during September 18-20, 2020. The conference was planned to take place in Honolulu, HI, USA and was changed to a virtual format due to the COVID-19 pandemic. The 14 full paper and 1 short paper presented were carefully reviewed and selected from 26 submissions. They deal with all topics regarding blockchain technologies, platforms, solutions and business models, including new blockchain architecture, platform constructions, blockchain development and blockchain services technologies as well as standards, and blockchain services innovation lifecycle including enterprise modeling, business consulting, solution creation, services orchestration, services optimization, services management, services marketing, business process integration and management.