An extensive literature examines educational inequalities such as racial/ethnic and socioeconomic status-based achievement gaps, as measured by standardized test scores, GPA, and other metrics of cognitive skills (Fryer & Levitt, 2004; Reardon et al., 2016). However, only recently have scholars, practitioners, and governments started paying more attention to inequalities in students' non-cognitive educational outcomes, including disciplinary outcomes (Skiba et al., 2014), behavioral skills (Waldfogel & Washbrook, 2011; Duncan et al., 2011), and self-control (Reardon & Portilla, 2016). While many scholars disagree about the definition and measurement of "non-cognitive outcomes" (Duckworth & Yeager, 2015), they all acknowledge the role of such factors (known variously as socioemotional skills, character skills, social skills, 21st-century skills, others) in child and adolescent development (Durlak et al., 2011; Heckman & Kautz, 2013). Building on this theme, my dissertation consists of three empirical chapters, with each chapter examining a different aspect of inequality in students' non-cognitive educational outcomes that can inform educational policy and practice. In the first chapter, I examine the disparities in "disciplinary outcomes"--such as expulsions and suspensions in school between white and Black students and between special education and non-special education students--using rich, administrative data on multiple cohorts of students in Indiana. In the second chapter, I evaluate the effects of a social-psychological intervention at two large public universities on increasing freshmen students' "sense of social belonging," which has previously been shown to reduce racial achievement gaps and racial disparities in rates of college persistence in smaller and more elite universities. In the last chapter, I investigate the links between the Black-white "disciplinary gap"--or differences in rates of suspension and expulsion between Black and white students--and racial academic achievement gaps. Together, these empirical chapters examine disparities (race-, socioeconomic, and special education-based) in a variety of non-cognitive educational outcomes using an interdisciplinary lens. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]