Many schools are beginning to serve breakfast after the bell (BAB) in order to expand breakfast participation. Improved nutrition may lead to better academic achievement, but BAB may also cut into instruction time. Using a difference-in-differences (DID) estimation with variation in treatment timing, we find modest negative effects of BAB on math and no effects on English, Language, and Arts (ELA) test scores. The negative effects, while small, were driven by more affluent children. The null findings cannot be explained by the lack of an effect on breakfast participation or school attendance increases. Average treatment effects by grade indicate positive effects on math scores for vulnerable children when BAB is adopted in earlier grades and negative but modest effects in later grades for more affluent children. Overall, we conclude that BAB can be incorporated into the school day without adversely impacting academic achievement in a meaningful way.