The goal of this case study was to explore how a mentor teacher used video-recorded co-planning sessions to reflect on and improve one's mentoring practice. Findings reveal ways in which the mentor used talk in co-planning sessions to model one's thinking process and to gradually release planning responsibility to engage the intern in learning to plan for instruction. Results show the importance of intentional educative co-planning, and the potential for supporting mentor-teacher development through the use of video to aid in reflecting on mentoring practice.