Counsellors are required to engage in supervision in order to reflect on, reflexively review, and extend their practice. Supervision, then, might be understood as a partnership in which the focus of practitioners and supervisors is on ethical and effective practice with all clients. In Aotearoa/New Zealand, there has recently been interest in the implications for supervision of cultural difference, particularly in terms of the Treaty of Waitangi as a practice metaphor, and when non-Māori practitioners counsel Māori clients. This article offers an account of a qualitative investigation by a group of counsellors/supervisors into their experiences of supervision as cultural partnership. Based on interviews and then using writing-as-research, the article explores the playing out of supervision’s contribution to practitioners’ effective and ethical practice in the context of Aotearoa/New Zealand, showing a range of possible accounts and strategies and discussing their effects. Employing the metaphor of threshold, the article includes a series of reflections and considerations for supervision practice when attention is drawn to difference.