This article focuses on an educational foundations-based professional development (PD) curriculum of antiracist conscientization we as two teacher educators designed and implemented with eight white practicing teachers in the Midwestern United States. We first articulate our conception of educational foundations and curriculum theory as a framework for our PD. We briefly review literature on other PD on race in the United States, outline our data sources, and describe the pedagogy and curriculum of RaceWork's Tripartite Model of race-visible and antiracist praxis. We then highlight, through interview data, the significance of group (relational) accountability and collaborative relationships that supported these teachers' self-designed antiracist interventions in their own unique school contexts during the 2-year PD experience. An ongoing, relationship-based PD model leading to material antiracist changes and practices points to a need for a broader, more holistic, and contextualized conception of antiracist interventions in U.S. public P12 school contexts, but also one grounded in the notion that in a white supremacist society, we (as race-visible white educators) are always "becoming" antiracist.