This paper reports research findings and discusses teachers' perceptions and implementation of the learner-centred approach to teaching English as a Foreign Language in Thai secondary school contexts. Case studies of five in-service EFL teachers from five contextually different public secondary schools in Udon Thani, Thailand were developed from interviews, classroom observations and teachers' self-reporting. The findings suggest that teachers were attempting to implement the learner-centred approach, but that they were not confident about its underlying theory, and therefore the degree of the implementation depended on how the teachers used their understanding of that theory in their practice within the contextual constraints.