Black Student Unions (BSUs) in higher education represent a valued resource as they often engage in activities to recruit and retain students from underrepresented communities. Student groups in higher education, however, are beset by a variety of institutional and contextual complexities and complications that can impede or derail their growth. Research investigating how to improve the success of ethnic student organizations (ESOs) could increase the flow of ethnic minority students through the higher education pipeline. The current study, an ecological systems analysis of four BSUs in higher education, examines the internal and external networks of these student organizations and tests the effectiveness of an ecological systems approach to assessing organization-context congruity. This study offers insights into BSU complexity and illustrates the role of context on BSU functionality. Findings indicate that BSUs make substantial contributions to their campus climate and suggest that BSUs thrive in environments that contain supportive resources, stabilizing institutional connections, and abundant collaborators. [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.]