This study investigates the associations between statewide affirmative action bans and the racial composition of undergraduate students at public 4-year colleges and universities in five states, that is, Arizona, Michigan, Nebraska, New Hampshire, and Oklahoma. I use the Integrated Postsecondary Education Data System data from 1999 to 2017, and find that despite having few selective postsecondary institutions, public four-year institutions in these five states experienced an average decline of 0.42 percentage points in the enrollment of underrepresented racial-ethnic minority students following bans on affirmative action. Further, the bans also decreased the enrollment of underrepresented racial-ethnic minority students at four state public flagship universities.