I analyze how two reforms, introduced to expand college access in Brazil, impacted enrollments of low-SES students. The first policy centralized applications in a nationwide platform (SISU), and the second expanded affirmative action quotas (AA) to a uniform share of 50 percent of vacancies offered by degree. Results show that SISU changes enrollment decisions of high-SES students, crowding out low-SES groups from the least competitive degrees disproportionately. In contrast, AA increases enrollments of low-SES individuals not only mechanically but also through behavioral responses. Finally, their interaction creates a complementary effect, protecting the low-SES groups from the crowding-out of centralization.