The Mindfulness-Based Interventions: Teaching Assessment Criteria (MBI:TAC) is a useful framework for supporting teacher development in the context of mindfulness-based supervision (MBS). It offers a framework that enhances clarity, develops reflexive practice, gives a structure for feedback, and supports learning. MBS is a key component of Mindfulness-Based Program (MBP) teacher training and ongoing good practice. Integrating the MBI:TAC within the MBS process adds value in a number of ways including: offering a shared language around MBP teaching skills and processes; framing the core pedagogical features of MBP teaching; enabling assessment of developmental stage; and empowering supervisees to be proactive in their own development. The paper lays out principles for integrating the MBI:TAC framework into MBS. The supervisor needs awareness of the ways in which the tool can add value, and the ways it can inadvertently interrupt learning. The tool enables skills clarification, but the learning process needs to remain open to spontaneous experiential discovery; it can enable structured feedback but space is also needed for open reflective feedback; and it can enable conceptual engagement with the teaching process but space is needed for the supervisee to experientially sense the teaching process. The tool needs to be introduced in a carefully staged way to create optimal conditions for learning at the various stages of the MBP teacher-training journey. Practical guidance is presented to consolidate and develop current practice. The principles and processes discussed can be generalized to other forms of reflective dialogue such as mentoring, tutoring and peer reflection groups.