From literary canons all the way to the motion picture industry, the artistic and popular cultural experience of marginalized or nonmainstream groups has been one of being represented by the other. In this article, we explore how online fanfiction, as an audience-driven, interactive form of writing, may offer a way for members of nonmainstream groups to push back against and offer alternatives to stereotypical and normative discourses. We focus on how autistic people, family members, teachers, and advocates cast autistic characters in their fanfiction stories, how these stories represent autism and how, given the affordances of an online publishing platform, audience members respond to such representations. Findings suggest that these online narratives diversify available representations of autistic characters; moreover, the interactive nature of the online publishing forum allows readers to respond to and potentially disrupt stereotypical thinking and common fictional tropes surrounding autism.