The study presented in this paper focuses on the change in identity experienced by teachers making the transition to teacher educators. The study is part of a larger research about the development of the profession and professional identity of teacher educators in the Netherlands. Formally, teachers become teacher educators the moment they start working at a teacher education institute. However, the development of an identity as teacher educator, and the knowledge, skills and attitudes that belong to this profession, is a long and complex process, which is often referred to as a ‘transition’ (Kosnik, 2007; Murray, 2008; Swennen, Volman & Van Essen, 2008). Based on a biographical research methodology approach (Kelchtermans, 1994), in-depth semi-structured interviews were conducted with five teacher educators. The participants differ in age, born between 1927 and 1966, gender, and the teacher education institute at which they worked or still work. Analysis of the results show that the participants’ identity as teacher educator is influenced by personal and social experiences, the educational context in which they work and the availability of a knowledge base and professional development opportunities specially designed for teacher educators.