When public schooling was first introduced in the United States, early proponents emphasized the need for mathematics as critical for an informed citizenry in a democracy. Half a century later, this purpose of mathematics has been almost entirely overshadowed by the push for mathematics to maintain technological and economic advantages. The belief that preparation for technological careers is, and has historically been, the only purpose for school mathematics in the US has become a myth widely believed by the public and policymakers alike. As this myth took hold, mathematics curricula were narrowed, incorporating only the mathematics, and applications of mathematics, that supported this specific purpose. Not only does this narrowing of school mathematics negatively impact the development of informed citizens, but it limits the extent to which mathematics can be studied in ways that engage all learners. The emergence of mathematics for social justice is thus—in part—an attempt to recapture the broader purposes of school mathematics.