This study explores mindfulness-based teaching and learning (MBTL) as an emerging field of transprofessional practice spanning educational, organisational, and clinical professions. Recognising the need for a more robust set of transprofessional MBTL teacher competencies to serve this emerging specialisation, the authors developed and validated the Mindfulness-Based Teaching and Learning -- Teacher Competency Framework (MBTL-TCF). Building on the pre-existing Mindfulness-Based Interventions-Teaching Assessment Criteria (MBI-TAC), the researchers developed a teaching framework for mindfulness specialists to reflect teacher agency, autonomy, and self-determination consistent with the purposes, traditions, and effects of what MBTL teaches: that is, mindfulness. The paper presents the sequence of construct, face, and content validation procedures, including the alignment of the MBTL-TLC with Dreyfus and other teacher competency frameworks from a range of sectors and countries. Finally, using an adapted Delphi process, a six-member international expert panel plus one diversity reviewer were invited to review and refine the emerging framework. The resulting MBTL-TCF presents 12 competency domains with associated activities and performance indicators.