Noting the benefits of mathematics in students’ future educational attainment and labor market success, there is considerable interest in high school requirements in terms of course-taking in mathematics at the national, state, and school district level. Previous research indicates that taking advanced math courses in high school leads to positive college outcomes. However, these studies often fail to account for the self-selection of students into curricular pathways that may result in biased estimates of the effect of course-taking on subsequent educational outcomes. Applying an instrumental variable (IV) approach, we investigate how the level of math courses a student completes in high school differently affects their chances of attending and completing postsecondary education. Using longitudinal student unit record data from Florida, our results indicate that a statistical model that does not account for students’ self-selection produces results different from a technique that corrects for this potential source of bias. Specifically, completing Algebra II significantly increases the probability of attending college, particularly two-year colleges, but has no significant effect on degree attainment.