The world needs a vibrant European open source ecosystem. As open source software has become mainstream how do we ensure it creates long-term value for all and enables good jobs and digital sovereignty across societies? The growth and sustainability of the ecosystem depends on the success of its stakeholders: open source projects and developers, open source foundations, systems integrators, software vendors, and users. We all play a part through our technology choices, our best practices, our engagement with other players. We each have a vested interest in the well-being of other stakeholders. OW2con’21 will address the many challenges of ensuring a sustainable European open source ecosystem.