This paper analyses Ambedkar's challenge to racial theories of untouchability. It examines how Franz Boas’ ideas about race, via Alexander Goldenweiser, influenced Ambedkar's political thought. Ambedkar is situated as a thinker aware of larger changes taking place in Western academia in the early twentieth century. During his time at Columbia University, Ambedkar familiarised himself with ideas that rejected the fixity of identities and racial hierarchies; following Boas, he rejected the idea that the untouchables’ place in society was determined by their supposed racial inferiority. Instead, he argued that untouchability was a cultural problem that could be stamped out.