We explore the discipline gap between Black and White students and between Hispanic and White students using a statewide student-level panel data set on Indiana public school students attending prekindergarten through 12th grade from 2008-2009 through 2013-2014. We demonstrate that the Black-White disciplinary gaps, defined in a variety of ways and robust to a series of specification tests, emerge as early as in prekindergarten and widen with grade progression. The magnitude of these disciplinary gaps attenuates by about half when we control for many student- and school-level characteristics, but it persists within districts and schools. In contrast, we find that Hispanic-White gaps are initially null and statistically insignificant at the prekindergarten/kindergarten level and attenuate substantially after adjustment for cross-school (district) variation and other covariates. We further disentangle the discipline gap using a decomposition technique that provides empirical support for the hypothesis that Black students nonrandomly sort into more punitive disciplinary environments.