Abstract
The purpose of this research was to develop the social interaction of children with autism in inclusive classrooms due to children with autism having marked impairments in social interaction. The research method was the research and development approach (R&D), while the target groups consisted of 3 children with autism at elementary level and 5 children with autism at secondary level studying in a full inclusion setting at Demonstration School, Khon Kaen University, Thailand. The research instruments consisted of interview form, social interaction checklist, manual and questionnaire. The data were analyzed via content analysis, cross case analysis and analytical description method. The research findings were as follows; children with autism showed increased development of social interaction in both communication skills and group activities. Moreover, students in normal classroom generally accepted and helped children with autism in regular activities. Teachers and parents also collaborated in the development of social interaction of children with autism. The processes of developing social interaction used the PDCA Cycle. The impact of development of social interaction had direct positive impact on the learning of children with autism in inclusive classrooms.