This paper describes an innovative use of Lesson Study (LS), an internationally used collaborative approach in which teachers develop their teaching knowledge and practices. It aimed to evaluate how EPs join teachers in LS teams, using working memory and other knowledge to inform the teaching of pupils with learning difficulties. The study uses a case study methodology to evaluate LS teams (three teachers and EP) in a primary, secondary and special school. The findings show how working memory knowledge is used in reviewing and planning research lessons, how the teams interact, including the teachers' perceived EP contribution to the Lesson Study process. The paper illustrates the potential of an inter-professional LS study to embody collaborative reflective practice in order to improve the teaching of pupils with learning difficulties.