Classroom teachers have encountered practical difficulties in responding to unique communicative and social needs of children with autism spectrum disorders (ASDs). Moreover, cultural values can affect teachers’ preferences for desirable skills. In a 9-week period in the first term of a primary school unit, three Japanese special education classroom teachers were interviewed about how they taught children with ASDs in a group, and video observations were made of their group lessons including children with ASDs. Thematic analysis of interviews showed these teachers highly valued a child’s engagement and peer interactions in their teaching and talked about making improvements in these areas throughout a series of structured group lessons. However, they provided reflective rather than systematic assessments of outcomes. Actual outcomes from quantitative measurements, obtained from video analysis, showed that children with ASDs became more engaged in their activities when the lesson was more structured and that they gradually interacted more with peers as the core lesson was reworked and taught again through the term.