Collaborative modeling is gaining a growing interest in both academia and industry. However, several research challenges remain open, including scalability, support for multi-user modeling environments, model versioning, migration, comparison, merging and conflict management. Recently, scientific research contributions related to collaborative model-driven software engineering (MDSE) are emerging, each of them focusing on different and specific aspects of collaboration and modelling. Still, many of these studies are scattered across multiple research areas such as software engineering, model-driven engineering, model integrated computing, etc. COMMitMDE 2017 has brought together researchers and practitioners to explore (i) the impact of collaborative SE methods and principles on MDE practices and (ii) how MDE methods and techniques can support collaborative software engineering activities. Also, the workshop aimed at assessing the state of the research and practice on Collaborative MDE, creating new synergies between tool vendors, researchers, and practitioners, informing the community about the new means for collaborative MDE, and identifying needs and research gaps in the collaborative MDE area.