Introduction: Educational change, particularly English language teaching (ELT) pedagogical reforms, has received much attention from language researchers in the era of globalization and internationalization, especially in Vietnam. Purpose: This study is aimed to investigate teachers' responses to ELT pedagogical reforms, what factors influence the responses, and if there are any differences in these factors among different groups of participants. Methodology: This study was conducted quantitatively, followed by qualitatively, i.e. a mixed method approach. The data were collected from 102 English as a foreign language (EFL) high-school teachers in the Mekong Delta in Vietnam. Findings: The results from the questionnaire and interview revealed that teachers highly accepted ELT pedagogical reforms. Besides that, the teachers were strongly affected by the influential factors, especially students' learning outcomes. Furthermore, the teachers with different educational qualifications were affected by the influential factors at different levels. Finally, the study found that the more teachers were affected by these factors, the more they accepted ELT pedagogical reforms. Based on these findings, implications were made for enhancing teachers' teaching practices in response to ELT pedagogical reforms.