Extension of retribution- and incapacitation-based criminal justice policies and practices to schools has exacerbated racial and ethnic disproportionality in school discipline, a serious and unsolved threat to equity in education and social opportunity. Common approaches implemented to reduce discipline disproportionality have not been shown to be widely effective. A more comprehensive, theory-driven understanding of the factors associated with disproportionate discipline is needed to enhance equity. In this article, we propose a conceptual model of how racial and ethnic bias affects school discipline, with direct implications for practical interventions. The model includes a multidimensional view of bias, informed by research from the field of social psychology, with multiple points identified for intervention to reduce disproportionality over time. The authors conclude with a proposed multicomponent intervention that builds on a foundation of school-wide positive behavioral interventions and supports (SWPBIS) and includes specific strategies for reducing the effects of explicit and implicit bias on school discipline decision making.