Individuals on the autism spectrum experience a wide range of support needs and it comes as no surprise that opinions differ as to the best way to provide necessary supports. Some articulate self-advocates argue that societal acceptance of neurodiversity is the key issue. These views have clashed with those of parents and professionals who advocate for access to evidence-based interventions for profoundly autistic children and adults. The consequences of these kinds of differing opinions are so far-reaching that the term “autism wars” was coined. In this article, we argue that although acceptance of diversity is obviously important, this should include an openness to diverse scientific traditions, especially if lack of such openness limits public policy and adversely affects individuals and families. “Open Science” holds much promise in many fields, but its influence cannot be taken for granted when it comes to evidence-based support practices that are grounded in the science of behavior analysis. Benefiting from open science in autism research requires well-developed advocacy skills. To illustrate, we use case studies from the UK, where advocates of open science have met with intractable obstacles.