This article proposes the concept ‘platformed racism’ as a new form of racism derived from the culture of social media platforms ‒ their design, technical affordances, business models and policies ‒ and the specific cultures of use associated with them. Platformed racism has dual meanings: first, it evokes platforms as amplifiers and manufacturers of racist discourse and second, it describes the modes of platform governance that reproduce (but that can also address) social inequalities. The national and medium specificity of platformed racism requires nuanced investigation. As a first step, I examined platformed racism through a particular national race-based controversy, the booing of the Australian Football League Indigenous star Adam Goodes, as it was mediated by Twitter, Facebook and YouTube. Second, by using an issue mapping approach to social media analysis, I followed the different actors, themes and objects involved in this controversy to account for the medium specificity of platforms. Platformed racism unfolded in the Adam Goodes controversy as the entanglement between users’ practices to disguise and amplify racist humour and abuse, and the contribution of platforms’ features and algorithms in the circulation of overt and covert hate speech. In addition, the distributed nature of platforms’ editorial practices ‒ which involve their technical infrastructure, policies, moderators and users’ curation of content ‒ obscured the scope and type of this abuse. The paper shows that the concept of platformed racism challenges the discourse of neutrality that characterises social media platforms’ self-representations, and opens new theoretical terrain to engage with their material politics.