National data have shown for decades that Black students experience more frequent and severe disciplinary actions that remove them from school (e.g., suspension), compared with their White peers. Despite extensive research documenting the sequelae associated with suspension (e.g., school drop-out and delinquency), there has been relatively scant research addressing the discipline gap as it relates to students' sense of belonging and equitable treatment at school, or to potential adjustment problems it may evoke. The present observational study examined the Black-White discipline gap in 58 high schools with a sample of 19,726 adolescents (Black n = 7,064, White n = 12,622) in Maryland. Employing a multilevel framework and leveraging data from the U.S. Department of Education's Office of Civil Rights and the student-report Maryland Safe and Supportive Schools (MDS3) School Climate Survey, we characterized 58 high schools by their excess in Black relative to White student risk of out-of-school suspension. We then assessed whether Black students' excess risk of out-of-school suspension was negatively associated with perceived school equity and school belonging, and positively associated with adjustment problems (i.e., externalizing symptoms) in a stratified analysis of White and Black students. We found that school-level discipline gaps were associated with Black students' perceptions of less school equity (? = -0.54, p < 0.001), less school belonging (? = -0.50, p < 0.001), and increased adjustment problems (? = 0.77, p < 0.001), even when accounting for student demographics (i.e., gender, grade level, socioeconomic status) and school-level contextual factors (i.e., socioeconomic status, student diversity, overall suspension rates), whereas these associations were not significant for White students. Study findings have implications for educational reform in high schools in which out-of-school suspension practices differ by race.