Beginning in the early 1990s, states and districts enacted zero-tolerance discipline policies that relied heavily on out-of-school suspensions. Recently, districts nationwide have revised these policies in favor of more tempered disciplinary responses. In 2012-2013, Philadelphia reformed its discipline policy to limit suspensions for nonviolent student misconduct and granted principals greater discretion in responding to more serious occurrences of student misconduct. Employing a difference-in-differences approach, we find that Philadelphia's reform resulted in a modest decline in suspensions for nonviolent infractions in the year of reform; however, total suspensions remained unchanged while serious incidents of student misconduct increased. Further, the truancy rate increased and district math and English language arts achievement declined following the policy reform. These findings should inform policymakers and practitioners on the implications of district-level reforms for suspension usage and the potential consequences for student outcomes.