This study explores how teacher educators involved in developing collaborative teacher research teams of pre-service and in-service teachers perceive their new role. Ten teacher educators in 9 teams were involved in a 1-year teacher research cycle. Thematic analysis was performed on the transcriptions of audio-taped group sessions, video diaries of the teacher educators, and field notes of the researcher. Three recurrent sub-roles of teacher educators as brokers between theory and practice were confirmed: researcher, coach, and mentor. A 4th sub-role as "learner" emerged from the data, stressing the preoccupation of teacher educators with their own professional development. The dynamics of teacher research teams shape the way teacher educators grow into their role as brokers: Teams with a high research disposition and self-regulation provide a better learning environment for teacher educators. We argue for the development of a systematic support programme for teacher educators who take on the role of broker.