We explore the effects of a statewide policy change that increased the number of high school math courses required for admission to four-year public universities in North Carolina. Using data on cohorts of eighth-grade students from 1999 to 2006, we exploit variation by district over time in the math course-taking environment encountered by students. Purely as a result of a student's year of birth and location, students faced different probabilities of encountering a sequence of math courses sufficient to qualify for admission. Within an instrumental variables setup, we examine effects of this policy shift. We find that students took more math courses in high school following the state's announcement, with relatively larger increases for students in the middle and bottom quintiles of their eighth-grade math test scores. Our results suggest this increased math course-taking led to higher high school graduation rates. It also led to increases in enrollment rates at universities in the University of North Carolina system, with the largest increases being in the quintiles of student achievement from which universities were already drawing the bulk of their enrollees. Finally, we find scant evidence of boosts in post-enrollment college performance due to increased math course-taking in high school.