Over the past three decades, American high school students' course taking has rapidly intensified. Between 1982 and 2004, for example, the proportion of high school graduates who earned credit in precalculus or calculus more than tripled. In this article, the authors investigate the consequences of mathematics curricular intensification for social stratification in American high schools. Using representative data from U.S. high school graduates in 1982, 1992, and 2004, the authors estimate changes in race-, class-, and skills-based inequality in advanced math course credit completion. Their analyses indicate that race, class, and skills gaps in geometry, Algebra II, and trigonometry completion have narrowed considerably over the study period. However, consistent with the theory of maximally maintained inequality, inequalities in calculus completion remain pronounced. (Contains 6 tables and 13 notes.)