Abstract
In L2 content-based classrooms, code-switching or translanguaging seem to be a common practice adopted by teachers. There has been growing research discussing the potentials of L1 in these classrooms. Most of the current studies have focused on the analysis of lesson interactions and yet the perception of the content teachers has remained underexplored. This case study investigated the introspective views of a group of content teachers at a secondary school using questionnaires and written accounts. Data analyses showed that these teachers were generally aware of the interpersonal and ideational functions achieved by the use of L1 and they also seemed to have a positive view towards their practices of using L1 in English-medium classrooms. Based on the findings, practical implications for content teachers in relation to making medium of instruction decisions and suggestions for further research are discussed.