Racially segregated cities tend to be politically polarized cities, leading to inequalities in public goods provision, political and social isolation, concentrated poverty and the perpetuation of a sense of hopelessness among many living in America’s urban centers. While the links between racial segregation and political polarization are well established, it is less clear why, or through what mechanism, both arise simultaneously. In this article, we derive a formal model which we demonstrate can partially account for this puzzle. This model allows us to derive “ideological tipping points”: changes in neighborhood demographics at which all members of one or more groups along the ideological spectrum (liberal, conservative, moderate) relocate. We then validate the model and demonstrate that racial segregation and political polarization consistently emerge in equilibrium under a wide variety of conditions by simulating movement of individuals between Census tracts in the largest 10 cities in the United States.