© 2019 JLLS and the Authors - Published by JLLS.This study aims at examining the functions of 4 teachers’ and their students’ code-switching in tertiary-level EFL classrooms and the teachers’ perceptions of code-switching. Data were collected by video-recording of the lessons of each teacher once a week and the classes were video-recorded in a three-week period. After transcribing video recordings of their lessons, the data were analysed qualitatively by finding the code-switching functions of teachers and students and finding if there are any similarities and differences between novice and experienced teachers’ code-switching functions. Moreover, semi-structured interviews were also carried out with the teachers to get their perceptions of code-switching. Results of the study showed that teachers did not use code-switching most of the time in teaching, there were a few instances. Of these instances, some similarities and differences among teachers’ and students’ functions of code-switching, and also between novice and experienced teachers’ use of code-switching in classroom discourse were detected. Furthermore, interviews revealed that what the teachers do in the classroom in terms of code-switching and their perceptions on code-switching matched. Based on the results, some implications were mentioned in terms of the use of L1 in language classes.