This chapter examines connections between gender performance and the concept of authenticity in three types of cosplay: crossplay, “trans” cosplay, and erotic cosplay. Cosplay is a fan practice in which the body of the cosplayer (who takes on various roles such as audience, craftsperson, performer, editor, and distributor) is crucial, both to their own performance and experience in real time and to the creation of digital media, which is disseminated online and used by themselves and other fans for various purposes. I argue that the definition of authenticity articulated by cosplayers and their audiences shifts according to the goals of the cosplay, particularly when it is considered to include a gendered or sexual aspect. While a minority of cosplay practices are a site of deliberate and politicized articulations of non-normative models of gender, other types move away from “meaning-making” and questions of normativity or identity-based gender and sexuality, through affective response to the various bodies and images in their respective cosplay fandoms. The chapter brings these three gendered cosplay types together and compares their performances and fan reactions to those performances using affect theory. It demonstrates that fan culture encompasses traditional gender politics at times, but also declines to engage with such social issues in the quest of intense but more ephemeral embodied experiences that transform the value and definition of authenticity.