Taking into account the pressing need to understand more about what teacher educators' professional development characterises, this article adopts a mixed method approach to explore Flemish (Dutch-speaking part of Belgium) teacher educators' professional development needs and opportunities. Analysis results of a large-scale survey study with 611 teacher educators and analysis of five qualitative focus groups (with 24 teacher educators) are presented. The results confirm the lack of attention for teacher educators' professional development in the Flemish teacher education system. Moreover, the findings indicate a structural need for participation in professional development activities that are linked to teacher educators' own practices, organised as long-term sustainable professional development trajectories, and formally recognised. To conclude, a professional development agenda for research, policy and practices related to teacher educators' professional development is discussed.