Exploring research and different reports indicates that the school situation for autistic students may be challenging from the view of professionals, parents, and autistic students themselves, which may lead to an inequitably educational situation concerning this group of students. As such, this thesis aims to explore if and how professionals’ participation in professional development enhances the quality of education for autistic students, including the perspectives of autistic students, their parents, and professionals in pre-and primary school. Four studies have been conducted, their findings have been synthesized narratively to fulfil the aim of the thesis and answer the research questions addressed. Three key elements of changes were identified: Attitudes, knowledge, and strategies to accommodate, the latter not as evident. Discrepancies were detected across participants and contexts. Furthermore, the professionals identified barriers to implementation, such as lack of resources, physical environment, and enabling factors, such as participation (collaborative aspects).