This study contributes to the conceptualisation of teachers’ competence through a systematic review (a concept synthesis) of three key transdisciplinary competencies—teachers’ diversity competence, teachers’ research and development competence, and teachers’ digital competence. Based on our analysis, we propose a set of dimensions to consider—within which there were important tensions in the research literature reviewed—when discussing teachers’ professional competence. These dimensions are: the 1) beneficiary, 2) teachers’ role, 3) attitudes, knowledge and skills, 4) sources of competence, 5) relationship to disciplinary content and 6) assessment. We discuss the three areas in light of these dimensions. We suggest that the complexity of being and becoming a teacher is a blind spot in research on teachers’ transdisciplinary competence and that many articles show deficit thinking about teachers.