Teacher professional development is a key factor for transforming professional and school culture. This article describes a case study undertaken in a Spanish school during the 2007-2008 academic year. Our aim is to explain how action research methodology was applied to encourage professional and school culture towards an intercultural and inclusive approach. Our results show that the training process challenged teachers' pre-existing deficit theory perspectives and empowered them as leaders for school change. The conclusions identify the key factors that enabled teachers to engage in critical reflection, and to implement strategies for collaborative work and community participation in school.