Conditional on enrollment at a four-year public university, African American students are less likely to graduate and less likely to graduate with a STEM degree than White students. This article reports on evidence from Missouri showing that these outcome differences in college can be explained entirely by differences in students’ academic preparation prior to college enrollment. While this result should not be taken to imply that college-level interventions cannot help to reduce observed college success gaps by race, it does point toward pre-college interventions as being better targeted at their underlying source.