The continuing developmental process of learning mentoring, specifically regarding supporting teacher research, has received relatively little attention in fields such as English language teaching, and this qualitative case study addresses the gap. It explores how three teacher-research-mentors, who were experienced classroom practitioners but novices in research-mentoring, grew into their new role while supporting teacher research projects in different English language higher education contexts in Turkey over a one-year period. Vignettes reveal that they became conscious of needing to provide psychological support to sustain teacher-researchers' motivation from starting their research projects to completing them successfully, presenting findings and writing them up, and that they also developed in other roles, but as subject-specialists sharing knowledge about research to a lesser extent. Outcomes, in terms of the quality of research produced by the teacher-researchers in their contexts, appeared influenced by the different characteristics of their institutions and the degree of external support in the form of mentor-mentoring the teacher-research-mentors could access. Given the increasing interest around the world in teacher research as an empowering form of professional development, there is a growing need for teacher-research-mentors, and these findings, through shedding light on research-mentors' developmental needs, might be of interest to teacher educators.