Collaborative action research is effective to develop inclusive practices that offer relevant responses to students’ diversity. This research is based on an experience of teacher professional development carried out in 15 public schools of a municipality, by applying the Lesson Study (LS) method. The objective was to assess: the contributions of LS to teacher development with an inclusive approach, the changes in pedagogical views and practices it has promoted, and the factors that facilitate its sustainability. From a descriptive-interpretative approach, the data were collected through three focus groups in which participated 12 teachers from 5 schools and 9 facilitators, and documentary analysis of LS reports. The results show a positive appraisal of LS as a strategy for inclusion, highlighting that its greatest value lies in the opportunity to reflect and address problems of practice through collaboration between teachers. It also allowed teachers to broaden their conception of diversity, to become aware of the importance of considering the voice of students in pedagogical decisions, and to move the focus of attention from teaching to students’ learning and participation.

Professional development; Inclusive education; Action research; Lesson study; Collaborative work.