In recent decades, the black-white test score disparity has decreased, and the test score disparity between children of high- versus low-income parents has increased. This study focuses on a comparison that has, to date, fallen between the separate literatures on these diverging trends: black and white students whose parents have similarly low, middle, or high incomes (i.e., same income or race within income). To do so, I draw on three nationally representative data sets on 9th or 10th graders, covering 1960 to 2009, that contain information on students' math test scores. I find that math test score disparities between black and white students with same-income parents are to black students' disadvantage. Although these disparities have decreased since 1960, in 2009 they remained substantively large, statistically significant, and largest between children of the highest-income parents. Furthermore, family and school characteristics that scholars commonly use to explain test score disparities by race or income account for markedly decreasing shares of race-within-income disparities over time. The study integrates the literatures on test score disparities by race and income with attention to the historical and continued structural influence of race, net of parental income, on students' educational experiences and test score outcomes.