Inquiry-based teaching (IBT) is becoming more prevalent in educational settings. However, moving from lecture-centred teaching to inquiry-based teaching is not just a matter of policy making, but also requires a shift in teachers' mindsets as an essential step towards successfully promoting IBT. To understand how policy can be accepted, this study explored teachers' acceptance of IBT in the context of implementing a new general education curriculum in Vietnam. Taking teachers' self-efficacy (TSE) as a driving factor, how it related to teachers' perceived usefulness and perceived ease of IBT application, attitude, and intention to implement IBT was examined. Participants were teachers from junior and senior high schools in Hanoi, Vietnam. Data from 217 participants were subjected to structural equation modelling to verify the research model. Results indicated that TSE was positively associated with teachers' perceived usefulness and perceived ease of IBT implementation in their course instruction. Furthermore, these two variables were positively related to teachers' attitude towards implementing IBT. Ultimately, teachers' attitude was related to their intentions to continue using IBT. The implication of this study is that TSE plays the driving role in implementing IBT; thus, enhancing TSE appears to be the key to successfully implementing IBT.