The purpose of this article is to show how, in the United States, some states and school districts are transforming their curriculum through ethnic studies. Ethnic studies exists as a result of unequal power relations in which historically marginalized groups have not had the power to define how education will serve their own communities. According to its activists, ethnic studies not only teaches about the cultures of diverse groups, but also reconstructs, the curriculum around the counter-narratives perspectives, epistemologies, and visions of groups that have been treated historically as if their experiences and perspectives were of lesser value. The article begins with a theoretical framework that considers school knowledge as filtered through the perspectives of dominant groups. Sleeter then reviews research on the perspectives that structure the knowledge in school textbooks, showing how it represents narratives of dominant groups, and the impact of those perspectives on minoritized students. Then Sleeter considers ethnic studies as counter-narrative, and reviews research on the academic impact of ethnic studies on students. A limitation of the implementation of ethnic studies is that it addresses specific courses rather than transforming the whole curriculum. Sleeter developed a framework to help teachers transform their lessons and units in all disciplines, using the central ideas of ethnic studies; this framework is presented. The article concludes with a few implications for Spain from this work in the United States