The present study explores pre-service English teachers' perceptions before and after performing a teaching practicum in Korean secondary schools. A total of thirty-two college students majoring in English education completed the questionnaire survey before and after the practicum. The collected data were analyzed using frequency and content analysis. The results of the study indicate that the pre-service teachers considered their university English curriculum suitable for teacher training before the teaching practicum but evaluated it more negatively afterwards. Regarding the effectiveness of the teacher training, the teaching practicum was deemed the most effective aspect before as well as after the teaching practicum. The pre-service teachers assumed that they would learn the most about how to plan their lessons before the teaching practicum. However, they learned the most about how to interact with students in reality. The results also reveal that the teaching practicum more effectively helped the pre-service teachers become familiar with the procedure of the class. In addition, the pre-service teachers felt that they could grasp their own strengths and weaknesses through the classroom observation over the duration of the teaching practicum. Pedagogical implications and suggestions for pre-service English teacher education are made based on the findings of the study.