English has marked its presence in all genres and poses pedagogical implications for teachers in a multilingual society. This paper aims to explore how Vietnamese English teachers in the Second Language (ESL) settings are aware of how and when to use codeswitching (CS) as a teaching strategy, its application and the main factors that affect the CS application in the classroom. The study uses qualitative approach and employs the case study design. A group of ESL teachers has been interviewed at two different Primary schools in Hoabinh, Vietnam. The results show that the teachers are inclined to use Code-switching as a successful classroom teaching strategy, particularly for guiding language learners. Therefore, this study implies that Codeswitching could be an effective strategy for the low proficient learners.

Keywords : Code Switching (CS); Effectiveness; Second Language (L2); First Language (L1); Teaching English; English as a Foreign language (EFL).