With the aim of helping to enrich teacher training processes, using an approach based on Practical Knowledge and Practical Thinking (Schön's knowledge-in-action), the present paper strives to explore and understand the relationships between espoused theories and theories-in-use (action theories by Argyris) of a group of seven pre-school teachers involved in a process of in-service training based on Lesson Study, a powerful
methodological tool to identify, contrast and review such theories both autonomously and cooperatively. The conclusion reached is that this training strategy is a rich proposal for the questioning of teaching theory and practice, and, in consequence, for the reconstruction of more unconscious Practical Knowledge, albeit with some circumstantial and personal nuances.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech