This book constitutes the refereed proceedings of the 11th International Symposium on Business Modeling and Software Design, BMSD 2021, which took place in Sofia, Bulgaria, in July 2021.The 14 full and 13 short papers included in this book were carefully reviewed and selected from a total of 61 submissions.  BMSD is a leading international forum that brings together researchers and practitioners interested in business modeling and its relation to software design. Particular areas of interest are: Business Processes and Enterprise Engineering; Business Models and Requirements; Business Models and Services; Business Models and Software; Information Systems Architectures and Paradigms; Data Aspects in Business Modeling and Software Development; Blockchain-Based Business Models and Information Systems; IoT and Implications for Enterprise Information Systems. The BMSD 2021 theme was: Towards Enterprises and Software that are Resilient against Disruptive Events.