Disproportionality is defined as the extent to which membership in a given group, such as gender, race/ethnicity, or socioeconomic strata, differentially affects the probability of a given outcome (e.g., being placed into special education or being assigned an out-of-school suspension). Underpinnings of disproportionality study include the broad sociohistorical and sociocultural issues of equity and social stratification by race, language, class, and ability that place already marginalized groups at a disadvantage. Though federal and state agencies have identified overrepresentation of students from racially and ethnically diverse backgrounds in both special education and exclusionary discipline as a significant problem in the field, quantitative studies have presented inconsistent findings on whether or not students from ethnically and racially diverse backgrounds are overrepresented in special education, and studies related to reduction of disproportionality in exclusionary discipline are scant. A broad understanding of social inequalities writ large may be the first step in mitigating these phenomena. This dissertation research aims to increase collective understanding of these processes.