For the best student outcomes, teachers need to engage in continuous professional development. As a result, models of teacher professional development have been developed, among which is the Critical Friends Group (CFG) technique. However, whether it works well with EFL teachers in an Asian context like Vietnam, where EFL teachers in particular do not seem to have the habit of working together, is as yet undiscovered. This study aimed to explore the experiences of a small group of Vietnamese EFL teachers during their participation in a CFG over one semester in a specific context in Vietnam. Through observations and interviews, this study offers insights into the participants' experiences as well as the application of CFG as a model of EFL teacher professional development in Vietnam.