Day by day, the importance of English is increasing in many areas of life. While learning a language, it is significant to develop four language skills. However, since vocabulary knowledge may provide basic communication for the students, it is vital to teach it systematically. While teaching vocabulary, teachers use various techniques. Some of them try new techniques, while some prefer to teach in the way they learned. These differences lead to different levels of vocabulary achievement. In that sense, it will be of great help to conduct research on discovering the self-concepts of pre-service English teachers for teaching vocabulary. The study aims to conduct mixed-method research to discover the self-concepts of 3rd year English Language Teaching (ELT) students who are teacher candidates. In this study, the participant group has been chosen according to convenience sampling, and semi-structured interviews have been conducted. According to the results of the present study, English teacher candidates need training related to vocabulary teaching in their senior year to avoid their possible self-discrepancy problems. The results of the present study will shed light on language teacher educators to prevent possible problems for future English teachers. In that sense, it is vital to learn self-concepts to create the most effective method for language teachers to use.