Research into factors underlying the dissemination of evidence-based practice is limited within the field of Applied Behaviour Analysis (ABA). This is pertinent, particularly in the UK where national policies and guidelines do not reflect the emerging ABA evidence base, or indeed policies and practices in other parts of the world. Within autism education there is evidence to suggest that parents are amongst the key decision makersoften not necessarily by choice but because of a lack of, or contradictory, information provided by professionals. Theories of evidence based practice in education and public services suggest that the 'perceptions' of decision makers are significant facilitators of, and barriers to, research utilisation. Whereas education and health professionals tend to view evidence in more scientific terms often regarding randomised control trials as 'gold standard', for others, including parents, experiential and anecdotal evidence can be as important. This study is the first to try to identify and quantify UK parents' beliefs about ABA in the education and support of children with autism. We developed and tested, using an internet survey method, the Parental Beliefs about ABA and Autism scale (P-BAA). Current and/or past use by parents of any behaviorally based approach including ABA was a significant predictor of P-BAA scores as were parent education, household income and child diagnosis: experience of a behaviorally based approach, higher levels of education and income and children at the more 'severe' end of the autism spectrum were associated with more positive beliefs about ABA.