Background: Access to Advanced Placement (AP) courses is stratified by class and race. Researchers have identified how schools serving disadvantaged students suffer from various kinds of resource deprivations, concluding that interventions are needed to equalize access to AP courses. On the other hand, the theory of Effectively Maintained Inequality (EMI) argues that schools serving advantaged students may perpetuate inequalities by expanding their AP curriculum so their graduates can be competitive in the college admissions process. Research Questions: Between 2000 and 2002, California attempted to expand AP offerings and enrollments. This study answers whether or not this intervention narrowed inequalities in AP along class and racial lines. It also examines if community affluence affects district officials' views of pressures to offer AP courses, which could explain any effectively maintained inequalities in AP access. Research Design: This study uses a panel dataset of all California public high schools from 1997 to 2006. It examines the changing effects of school poverty, upper-middle class presence, and school racial composition on offerings of and enrollments in AP subjects. It supplements the quantitative analysis with interviews from 11 school district officials in California conducted in 2006. Results: Hierarchical generalized linear models show that upper-middle class presence structures California high schools' AP subject offerings and enrollments, much more than school poverty. California's intervention resulted in increased AP subject offerings and enrollments in high schools serving disadvantaged and less advantaged students, but these reductions in deprivation had trivial effects on inequalities, since schools serving advantaged students increased their own AP offerings and enrollments. In addition, high schools serving White and Asian students had larger increases in AP offerings and enrollments than high schools serving Black and Hispanic students. Interview data indicate that officials in affluent districts perceived a greater demand for AP subjects, and were more likely to report their school staff was proactive to initiate new AP courses than officials in districts serving working-class communities. Conclusions: The findings document that while policies can increase AP access at schools serving low-income students, the actions of affluent schools and families will pose substantial barriers to achieving parity in AP offerings and enrollments. Moreover, studies gauging resource inequalities among schools may underestimate these inequalities if they use school poverty to measure schools' socioeconomic composition.