This article shares development of a mentor teacher training program to support teacher candidates in their student teaching internship. The mentor teacher training program includes three parts: (a) online training on internship processes and procedures, co-teaching, and a department developed Framework for Extended Oral and Written Feedback, (b) face-to-face orientation session to clarify co-teaching and feedback framework, and (c) co-observation of intern candidates by faculty supervisor and mentor teacher. The goal of the mentor teacher training program is to orient mentor teachers to the internship and to train them in providing high quality, actionable feedback that leads the teacher candidate to improved practice.