In this longitudinal study, we sought to better understand mentor teachers' perceptions of their roles as school-based teacher educators. We studied 11 school-based teacher educators and 123 teacher candidates, and collected data from observations, interviews, and artifacts. Using content and thematic analysis, the six roles of school-based teacher educators were identified: (a) host, (b) tour guide to the profession, (c) cheerleader/encourager, (d) planner, (e) instructional advisor, and (f) teaching partner. School-based teacher educators self-identified in the various roles as they interacted with the teacher candidates in their classrooms.