<p>Ableism is broadly defined as a set of behaviors and attitudes or, in behavior-analytic terms, as private events, deeply embedded within societal norms (Friedman &amp; Owen, 2017). This paper explores the concept of ableism and its relation to applied behavior analytic services, with a particular focus on its implications for services provided to Autistic people. The purpose of the paper is neither to criticize nor to offer apologies for applied behavior analysis (ABA), but rather it is to aid the reader in understanding ableism by describing the context in which applied behavior analytic interventions were designed to attenuate some of the severe behavior that was distressing for the Autistic person and their caregivers (e.g., parents, staff). Examples of such behavior included self-injury, aggression, and extreme social withdrawal which were characteristic of individuals diagnosed as Autistic in the early days of ABA. The authors trace the evolution of ableism in ABA through to the present day, in which the heterogeneity in behavioral expression and needs of people diagnosed as Autistic are perhaps greater than ever, and some of those needs continue to go unaddressed. This paper, along with its companion article, “Ableism in Applied Behavior Analysis: A Beginner’s Guide to Understanding and Dismantling Ableism in Practice with Autistic People,” have incorporated both the limited available research regarding ableism in ABA-related services and lived experiences of some of the authors and other Autistic people whom the authors have provided services.</p>