Mandatory uniform policies have been the focus of recent discourse on public school reform. Proponents of such reform measures emphasize the benefits of student uniforms on specific behavioral and academic outcomes. Tenthgrade data from The National Educational Longitudinal Study of 1988 was used to test empirically the claims made by uniform advocates. The findings indicate that student uniforms have no direct effect on substance use, behavioral problems, or attendance. Contrary to current discourse, the authors found a negative effect of uniforms on student academic achievement. Uniform policies may indirectly affect school environment and student outcomes by providing a visible and public symbol of commitment to school improvement and reform.