Abstract Teacher education programs have a vital role in developing student teachers’ professional identity as an effective factor in successful teaching. Though the number of studies regarding foreign language teachers’ professional identity development continues to proliferate, little attention has been paid to Iranian EFL student teachers in terms of different aspects of their professional identity being developed during their training at Teacher Education University. Adopting constructivist view (Berzonsky,1986) on identity formation, the present cross-sectional mixed-method study was conducted to explore and compare the professional identity formation of EFL student teachers at Iranian Teacher Education University within Kelchtermans’ (2009) comprehensive and dynamic framework for teachers’ professional identity. The participants were 350 EFL student teachers at three transitional stages of their education: entry level, just before participation in fieldwork practices, and exit level from four male and four female teacher education colleges around the country. The study also attempted to highlight differences between male and female participants. Sixteen participants, eight males and eight females, accepted the invitation to be interviewed. Six scales that were integrated into one 106 items, Likert-type questionnaire as well as semi-structured interviews were the employed instruments for data collection. According to Kelchtermans (2009), student teachers’ professional identity comprises five interdependent and mutually compatible aspects, namely self-image, self-esteem, job motivation, task perception, and future perspective. Expected teacher selves and Feared teacher selves scales (Hamman et al. 2013), Rosenberg’s (1965) widely-used Self-esteem scale (RSES), prospective teachers’ career choice opinionnaire (Fox, 1961), “Perception of effective foreign language teacher” scale (Brown, 2009), and Darling-Hammond’s (2006) scale for assessing student teachers’ perceived preparation at teacher education university were used to assess these aspects respectively. With the exception of job motivation, which varied due to cultural, social, and personal factors, the other aspects of professional identity developed positively from the first-year group to the last-year group. Almost in all aspects, females showed stronger perceptions of their professional identity development than males. The study put forward some implications for teacher education programs to support EFL student teachers in their lifelong journey to form and reform their professional identity. In addition, limitations of the study and suggestions for future research are presented. Keywords: EFL student teachers, Professional identity, Self-image, Self-esteem, Task perception, Future perspective, Teacher Education University
