An exploratory study to investigate the usefulness of a personalised, in-school cognitive-behavioural intervention (The Homunculi Approach) in supporting emotional regulation in primary aged children with Autistic Spectrum DisorderBackground: Emotional regulation impairments are considered a key difficulty for children with ASD, and disrupted emotional regulation is likely to be a factor contributing to challenging behaviour that children with ASD often present with. There is a growing evidence base for using CBT with children with ASD. A gap in the literature highlights a need for research which explores the use of CBT with key stage two pupils with ASD, specifically to address emotional regulation difficulties. Participants: Three year 4 and 5 pupils with a diagnosis of ASD and identified difficulties with emotional regulation were recruited from two mainstream primary schools. The views of their parents and teachers were also gathered.Methods: An exploratory multiple-embedded case study design was employed involving three cases from two settings, using qualitative and quantitative data collection at three time intervals. The quantitative measures consisted of pupil, parent and teacher measures of pupil emotional regulation skills, and the qualitative measures took the form of semi-structured individual interviews with pupils and teachers. Analysis/ Findings: Data were analysed using thematic analysis and descriptive statistics. Each case was analysed individually followed by a cross-case analysis. Findings are discussed in relation to implications for the use of CBT with ASD for emotional regulation and the role of the EP. Conclusion/ Implications: The study extends understanding about utilising CBT to support the development of emotional regulation skills in children with ASD. It also adds to the literature on adaptations needed to enable children with ASD to access CBT. Suggestions are made for future research regarding supporting emotional regulation skills in children with ASD.