Supervisors play a critical role in fostering teacher candidates' reflective thinking on their practice, yet too often it is the supervisor, rather than the teacher, doing most of the observation work. Video-based supervision offers a promising alternative, as teachers have an opportunity to examine their own lesson and thus engage with the supervisor in a more collaborative conference. In this paper, we explore the ways supervisors approach video in their conferencing with teachers as a vehicle for teacher reflective practice at one TESOL master's program in the USA. We examine what supervisors find salient in video observations, how they approach teachers when reviewing a lesson using video as a means to ground observation in evidence, and the struggles they encounter when trying to foster teacher reflection. We conclude with suggestions for implementing video-based supervision.