This study aimed at exploring teachers' perceptions of reflective teaching strategies in their teaching practice and the barriers that hinder the implementation of reflective teaching strategies. Quantitative and qualitative data were obtained by using a questionnaire and semi-structured interviews. The study took place in the context of high schools in most of the provinces in the Mekong Delta. The respondents involved in this research were fifty English as a foreign language (EFL) high-school teachers. The results revealed that most teachers have positive perceptions of the significance of reflective teaching strategies in their teaching. At the same time, the participants found barriers preventing them from implementing reflective teaching strategies in their language teaching such as lack of awareness of reflective teaching strategies, time or workload limitations as well as some obstacles related to the application of peer observation as a strategy of the reflective process. Finally, accordingly, the findings gained from two types of research tools, some pedagogical implications, and research suggestions on the effectiveness of EFL teachers' application of self-reflection strategies in the teaching-learning process were proposed in the study.