Research suggests that solidarity between people of color (PoC) is triggered when a marginalized ingroup believes they are discriminated similarly to another outgroup. This evidence has primarily focused on Asian Americans, Latinos, and Middle Eastern people, who are systematically discriminated against as foreigners. Yet evidence remains absent on Black people, who are systematically discriminated against as inferior, but not as foreign. Using a pair of pre-registered experiments with Black and Latino adults (N = 2060), we manipulated a shared sense of discrimination as inferior (“second class citizenship”). This treatment measurably increased Black solidarity with PoC, which then significantly boosted their support for pro-Latino policies (e.g., less Border Patrol agents along US-Mexico border). This pattern was reciprocated by Latinos, whose heightened solidarity with PoC increased their support for pro-Black initiatives (e.g., endorsing #BlackLivesMatter). Sensitivity analyses further establish this pathway’s viability. We discuss the implications for more effective coalition-building among racially minoritized groups in US politics.