The aim of this study, conducted in Sweden, was to investigate the cultural barriers between school personnel (teachers and principals) and nonschool personnel (a resource team), who were external to the school system, regarding consultation about challenging or difficult-to-teach students. Focus groups with teachers, principals, and the resource team as well as interviews with students and parents were conducted. The qualitative analysis resulted in a grounded theory of change resistance in the context of school consultation. Differences in professional assumptions led to conflicting professional main concerns. An intergroup conflict was inevitable in many cases and the professional cultural barriers that remained produced and reinforced professional ethnocentricity. This contributed to a lack of integration between external consultants and school personnel. Lack of integration contributed to the legitimacy loss and the maintenance of professional ethnocentricity. The basic social process of change resistance was centered in the interaction between professional ethnocentricity and lack of integration.