The authors studied changes in disproportionate exclusion of African American students, compared with their White peers, in relation to implementation of Schoolwide Positive Behavior Support using data from 46 schools. They measured (a) exclusion through suspension and expulsion data collected with the Schoolwide Information System; (b) Schoolwide Positive Behavior Support implementation through the Effective Behavior Support Survey completed by staff members; and (c) disproportionality with the relative rate index. Standard linear multiple regression analyses with the relative rate index as the outcome variable and Effective Behavior Support Survey items as predictors indicated specific Schoolwide Positive Behavior Support strategies, such as praise and positive reinforcement, were associated with reductions in disproportionate exclusions. Follow-up analyses with a subsample of eight schools that increased their Effective Behavior Support average score while decreasing their relative rate index identified additional strategies that hold promise for reducing disproportionate exclusion of African American students. (Contains 3 tables and 6 notes.)