This article reports on the professional development of teacher educators within the context of a national project, "Professional Quality of Teacher Educators," where a professional standard and a standards-based procedure of (self-)assessment and professional development have been created and effectively implemented. This project offered a unique opportunity to analyze the goals, activities and outcomes of the process of professional development of teacher educators in a situation in which this development is promoted by the professional group as a whole. In our research, we used 25 completed portfolio's made by teacher educators participating in the standards-based procedure of (self-)assessment and professional development. We found that teacher educators, participating in this procedure, prefer the development of their knowledge and skills over the development of their attitudes and beliefs. For their professional development, the teacher educators experiment with new activities within the work-situation and interact with colleagues within their professional community, more than that they study theory or reflect on their work. The participating teacher educators experience a positive impact at the personal level (change in cognition and behavior). More than one-third of them share outcomes with others. Above, they report a more positive self-esteem and more enthusiasm for teacher education. This article may motivate other countries or institutions to invest in the professional development of teacher educators. Further research is necessary on the essence of the professional qualities of teacher educators and the relation of their professional development with student learning. (Contains 7 tables and 4 notes.)