This dissertation defines “amateurism” to include a characteristic set of beliefs, a body of knowledge, and a way of knowing, all organized around the principle that it is possible, and perhaps preferable, to play music without established musical knowledge. I investigate how musicians confront hierarchies, both political and epistemological, with an amateurist insistence on their ability to perform without established knowledge. Typically, established musical knowledge conforms to standards and norms of technique, training, or education, which enact a powerful regulation of musical cultures. Through my research, I found that musicians who appear to lack or reject musical knowledge entirely nevertheless rely upon a wealth of subjugated epistemes and that every musical performance draws upon some type of knowledge. I examine four examples of musical amateurism from London and New York City in the 1970s in order to describe the use of amateurism as a political tool to critique epistemological hierarchies. Each example highlights musicians who articulated participation as a central tenant of their alternative episteme, in contrast to established musical knowledge. Each example highlights musicians who articulated participation as a central tenant of their alternative episteme, in contrast to established musical knowledge: 1) Cornelius Cardew’s attempt to create an anti-hierarchical experimental ensemble (Scratch Orchestra) that united skilled composers and untrained amateurs; 2) the widely-accepted claim that the Sex Pistols, and punks generally, could not play their instruments; 3) how “no wave” musicians, including Lydia Lunch, drew on supposedly instinctual performance practices to supplant technical instrumental skills; and 4) how amateurism became racialized as “primitive” when white downtown musicians confronted black rap musicians from Harlem and the Bronx. Whether these musicians were authentically able to disestablish hierarchies, or whether they merely re-codified their bodies of knowledge, depends on whether one wants to give a reading that gives undue force to the political possibility of musical amateurism. I argue that these performers’ appeals to musical amateurism effectively upset prevailing notions of musical knowledge in the 1970s, even if they themselves were limited in their ability to reconfigure power structures.