This study investigates the conceptualization and historical practice of solidarity primarily through the lens of African American, Chicana/o/x, and Puerto Rican sites of struggle in the twentieth century. Important to this investigation are the ways regional differences and geo-historical contexts facilitated articulations of Black-Brown/Afro-Latinx diasporic solidarities and how these articulations led to counter hegemonic activities and theories of revolution across local, national, and transnational boundaries. Through a relational and comparative framework, the study will ground these analyses in historical activities in the Midwest, Texas, California, and New York in the burgeoning Black and Brown Power movements at the mid- to late twentieth century.