Recent research suggests that high-stakes standardized testing has played a negative role in the segregation of children by race and class in schools. In this article we review research on the overall effects of segregation, the positive and negative aspects of how desegregation plans were carried out following the 1954 Supreme Court decision "Brown v. Board of Education," and the de facto re-segregation that followed the dismantling of many desegregation plans, along with the increase of school choice plans. We then analyze these effects in light of the ways that high-stakes standardized testing has grown in importance and intensity in US education policy and practice, especially during the most recent period of school re-segregation. Based on the evidence we argue that the intrinsic features of high-stakes testing, combined with current systems of school choice, function as mechanisms used for racial coding that facilitate segregation and compound inequalities found in schools.