This article reports on the use of portfolios to develop ELT major student-teachers' autonomy. The research was carried out for 14 weeks with twenty-one 3rd grade student-teachers in the English Language Teaching Department of Cukurova University, Adana, Turkey. To evaluate the impact of portfolios on fostering the participants' autonomy, data were collected from an autonomy readiness questionnaire, semi-structured interviews with the student-teachers and three portfolio evidences: graded goal sheets, reflection reports, and cover letters. The findings revealed that the use of portfolios assisted the student-teachers in becoming autonomous in regard to their personal and professional development and that the student-teachers perceived the portfolio process they went through positively. (Contains 6 tables.)