Brand activism occurs when a company adopts a value-driven non-neutral stance on a sociopolitical issue (Vredenburg et al., 2020). While generally analyzed as an emerging marketing strategy (Moorman, 2020), this chapter asserts that Barbie has embodied brand activism from the moment her 11.5-inch frame appeared on television screens in 1959. Recently, social media have played a significant role in this evolution, empowering Barbie to reach a broader audience and engage in meaningful conversations about controversial issues that resonate with her target audiences. Therefore, this chapter incorporates cultural branding (Holt, 2004) and stakeholder theory (Laczniak & Murphy, 2012) to conduct a genealogy of Barbie and a thematic analysis of its @Barbie Instagram and TikTok accounts to provide a historical overview of Barbie as a brand activist and to examine its modern social media-based #Barbie activism. Through these analyses, this chapter examines the perceived authenticity of Barbie’s activism (Vrendenburg et al., 2020); provides insights on how Barbie’s consumers likely inform the issues and the stances that the brand takes; and demonstrates how various media, especially social media, have influenced Barbie’s trajectory from feminist icon to an object that reinforces harmful gender stereotypes back to a social activist.