This dissertation explores the transformation of radical Black women’s internationalist politics during and after the Black Power era. This dissertation emerged from two central questions: Did U.S.-based Third World (inter)nationalisms of the late 1960s and 1970s influence the development of Black feminism? What role did internationalist politics emphasizing anti-capitalism and anti-imperialism play in the articulation of intersectional politics within Black feminist organizations? Blending biography and Black women’s intellectual history, this project traces radical Black women’s internationalism along two poles: the formation of the first Black feminist organization, the Third World Women’s Alliance across the years 1968-1970 and the Black feminist reshaping of the D.C. Rape Crisis Center from the mid-1970s to the 1980s. I argue that anti-carceral and reproductive justice politics tied together by frameworks of internationalism and intersectionality contributed to the development of Black feminist politics of the 1970s and 1980s. Chapter 1 analyzes the politics of the Third World Women’s Alliance in New York City and the Bay Area of California. The chapter demonstrates that Black and women of color feminists in the Third World Women’s Alliance mobilized campaigns for reproductive freedom and against state imprisonment and repression of people of color in the United States using appeals to Third World solidarity. The remaining chapters of the dissertation pivot to the D.C. Rape Crisis Center as a locus for the development of Black feminism. Chapter 2 traces the Black feminist transformation of the D.C. Rape Crisis Center, founded in Washington, D.C. in 1972 as one of the first rape crisis centers in the United States. The work of Nkenge Touré and Loretta Ross drove the institution to serve Black women and to adapt intersectional politics attuned to global systems of racism, capitalism, and colonialism; this process also influenced the development of a global vision of reproductive justice. Chapters 3 and 4 further investigate the importance of internationalist politics to specific D.C. Rape Crisis center organizing projects: the campaign to free Dessie X. Woods after her incarceration for self-defense against white sexual violence and the Center’s work with Prisoners Against Rape at Lorton Reformatory.