This research is the first in the UK to explore siblings and Group Leader's experiences of autism specific support groups. Increasingly there is recognition of taking a systems approach to children with autism and the needs of their siblings. However, very little is known about sibling support groups in the UK and about the impact of support groups on siblings of children with Autism Spectrum Disorders. The research explored the Group Leaders experiences of setting up and running autism sibling support groups and the sibling's experiences of the support groups. Semi structured interviews were carried out with siblings and group leaders. Michael Fullan's model of organisational change was used to explore group leader's experiences of setting up the groups. The FRAME (fun, relieve isolation, acknowledge feelings, model coping strategies and enhance knowledge) framework advocated by Sibs, a UK charity, was employed to explore the sibling's experiences of the groups. Theoretical `top down' thematic analysis was conducted on the two data sets. A number of conclusions were drawn from the findings. The GLs identified siblings of children with ASD as a vulnerable group which required support and so filled a gap in services by initiating and advocating for groups. The group format varied from one day to longer term. There appeared to be more benefits from attending longer term groups compared to one day groups however all groups clearly benefitted those who attended them. FRAME served as a useful framework for planning sessions for the group however it was recognised that tailoring activities to the siblings needs was important. Most GLs obtained siblings views at the start and throughout sessions to ensure their needs were being met. The sibling's experiences of living with a sibling with ASD were consistent with previous research findings and reported both positive and difficult experiences. The children reported positive outcomes from attending the siblings support groups, these were; having fun, making friends, discussing feelings, learning more about autism and learning new strategies to cope. The benefits of the support groups were threefold; they offered social, educational and therapeutic support. Finally, implications and recommendations for supporting siblings of children with ASD are discussed. The future of support groups for siblings of children with ASD relies on becoming embedded in organisation's structures and policies. This research provides evidence to advocate for holistic support to the family and not simply centre support on the diagnosed child and parents.