ObjectivesMindfulness-based supervision (MBS) is a vital support for teachers of mindfulness-based programmes (MBPs), and good practice guidance requires mindfulness teachers to have at least 4 hr of MBS a year. Despite this, underpinning theory and research on MBS is sparse. This study explores the perspectives of supervisors and supervisees to identify helpful and unhelpful processes within MBS.MethodA total of 12 supervisors and supervisees participated. Two phases of semi-structured interviews took place, the first with all 12 and the second phase with a selected six participants. A conceptual model of how MBS affects the teaching of MBPs was developed using a constructivist grounded theory approach.ResultsAll participants spoke of how MBS is a highly experiential way of developing skills to competently teach MBPs, supported through the relationship between supervisor and supervisee. MBS uses a mindfulness-based relational inquiry process characterised by specific ways of speaking, listening, and pausing. This inquiry supports the supervisee to cultivate an embodied way of knowing, a deliberate stance of “not knowing”, and to take an approach mode rather than avoidance mode towards vulnerability. During the interviews, participants emphasised the collaborative approach within MBS, but showed little acknowledgement or recognition of the inherent power with the role. Potential tensions in the holding of professional and ethical frameworks within MBS were identified.ConclusionsRecommendations are made about how the key findings can be brought into the ongoing good practice within MBS. Future changes within MBS should address issues of bias, diversity, and inclusivity.