The purpose of this multiple case study was to identify threshold concepts in the careers of educational developers. Twenty-one common threshold concepts emerged, with one threshold concept common among all participants: Facilitating a change process. The remaining 20 threshold concepts were captured in the following three categories: (1) Ways of knowing and being that facilitate change in individuals and in groups; (2) Ways of knowing and being that facilitate systemic change and (3) Core ways of knowing and being. Study results may provide guidance for the design of initial and ongoing formation programmes in educational development.