This book contains the proceedings of two long-running events held along with the CAiSE conference relating to the areas of enterprise, business-process and information systems modeling: * the 21st International Conference on Business Process Modeling, Development and Support, BPMDS 2020, and * the 25th International Conference on Exploring Modeling Methods for Systems Analysis and Development, EMMSAD 2020. The conferences were planned to take place in Grenoble, France, during June 8-9, 2020. They were held virtually due to the COVID-19 pandemic. For BPMDS 13 full papers and 1 short paper were carefully reviewed and selected for publication from a total of 30 submissions; for EMMSAD 11 full papers and 4 short papers were accepted from 29 submissions. The papers were organized in topical sections named as follows: BPMDS: Business process execution and monitoring, BPM applications in industry and practice, planning and scheduling in business processes, process mining, process models and visualizations EMMSAD: Requirements and method engineering, enterprise and business modeling, software-related modeling, domain-specific modeling, evaluation-related research.