Though racial affirmative action (AA) policies are widespread in college admissions, evidence on their effects before college is limited. We study a US Supreme Court ruling that reinstated AA in three states. Using nationwide SAT data, we separately identify positive effects of AA for Whites and underrepresented minorities. Using Texas administrative data, we find that AA narrowed racial gaps in grades, attendance, and college applications. Improvements in minorities’ precollege human capital and college applications are concentrated in the top half of the test score distribution among the students for whom the policy most increases the returns to human capital investment. (JEL H75, I21, I23, I28, J15, J24, K10)