This paper argues the importance of action research and critical reflection in the study of affective factors and language learning strategies in foreign language teaching. The starting point is a description of what affective factors and language learning strategies are and why Colombian EFL teachers should address these issues. Critical reflection and action research are, then, presented as rigorous and systematic activities that teachers could engage in to help their students deal with the emotional difficulties of social interaction and language learning, to open their own work to inspection and, more importantly, to construct valid accounts of their educational practices. Finally, action research is proposed as a powerful means for dev...