I study the efficacy of test-based meritocracy in college admissions by evaluating the impact of a grade-based “top percent” policy implemented by the University of California. Eligibility in the Local Context (ELC) provided large admission advantages to the top four percent of 20012011 graduates from each California high school. Estimates from a regression discontinuity design show that ELC led over 10 percent of barely-eligible applicants from low-opportunity high schools to enroll at selective UC campuses instead of less selective public colleges and universities. Half of those participants came from lower-income families, and their average SAT scores were at the 14 th percentile of their UC peers. Despite this mismatch, ELC participants overperformed in their college grades, and more-selective enrollment led participants to graduate earlier and earn higher late-20s wages by over $1,000 per percentage point change in their enrollment institution’s graduation rate. These returns appear to exceed the average return to university selectivity among higher-testing students in this setting, implying that university admission policies targeting low-testing students can promote economic mobility without efficiency losses.