This research explored the effect of adult interactive style on the spontaneous communication of children with autism. It focused on the frequency of children’s communication, the functions of their communication, the methods they used and the impact of four different school activities (i.e. sensory room, snack time, soft play and 1:1 work) on their communication. Theoretically, the study drew upon the transactional model of child development and the social model of disability. It was an action research study having a mix of quantitative and qualitative data which took place over an eighteen month period. The study was conducted within an Early Years Foundation Stage (EYFS) class in a specialist school for pupils with autism. Six children and three members of staff took part. The researcher developed a set of principles in conjunction with the staff which formed the basis for the Adult Interactive Style Intervention (AISI). The findings showed that staff increased their use of the AISI principles over time and all children considerably increased the frequency of their spontaneous communication, their communicative functions and methods. In the follow-up phase, twelve months later, it was found that these changes had been maintained in both children and staff.