Raising awareness of the teacher's role in creating conducive learning environments has not traditionally been part of the aims of EFL teacher preparation programmes. This longitudinal mixed methods study explores the impact of a 20-hour experiential in-service teacher development course with the knowledge base drawn from L2 motivation theory, group dynamics, and educational psychology. Quantitative (pre- and post-test questionnaires measuring students' perceptions of their classroom environment) and qualitative (regular course feedback, teacher interviews, lesson observations, and field notes) measures were employed to assess the course impact on cognitive and behavioural change of 8 self-selected non-native EFL teachers in Slovakia. The results show that, in most cases, no change occurred in spite of the teachers' endorsement of the course material, and several outer-context-specific factors are discussed to explain this negative outcome.