Intervention strategies in autistic spectrum disorder (ASD) have emanated from a range of theoretical perspectives with a consensus view that the greatest impact on children's subsequent development is likely to occur when this work is early, intensive and focuses on young children in the context of the family. Controversies in ASD intervention have arisen in relation to claims for effectiveness, particularly for versions of Applied Behavioural Analysis. Taking account of user perspectives, the evidence base for ASD intervention is considered, distinguishing between experimental work that identifies a treatment effect and research that establishes ecological validity. In order to move practice forward, research is required to address which programme components are helpful for which children and which families in which contexts. Drawing on current intervention research (South West Autism Programme), this paper concludes by outlining some of the factors that need to be considered in shaping future ASD research and ASD service provision.