This paper presents a four-year longitudinal study of student teachers' beliefs about language learning and teaching over the course of an English teacher education (ELT) program. The study attempts to track possible changes in the beliefs and to analyze the impact of an ELT pre-service program by taking the program itself as a dynamic variable. Interviews were conducted with 49 student teachers for four years, and the data were processed through a mixed-method design. The results of the study indicate that different phases of the program resulted in various changes at certain degrees. Student teachers' engagement in the teaching practicum seems to have a higher impact on the development of the beliefs about language learning and teaching. The findings may be influential in developing and designing more effective ELT programs. (Contains 5 tables.)