The purpose of this study was to examine variation in assistant principal (AP) social justice beliefs and high-stakes accountability perceptions and explore how APs balance accountability policies while addressing social justice issues in their schools. 79 assistant principals participated in a phase 1 survey with 10 APs selected to participate in phase 2 interviews. Findings revealed divergent AP views across social justice and accountability beliefs. APs are not a monolithic block, but individuals with complex histories, working in distinct organizational contexts that shape their ongoing sensemaking and nuanced perspectives regarding social justice leadership and high-stakes testing accountability. Findings drove recommendations for policy, practice, and future research by connecting what APs shared regarding leadership balancing actions that support social justice goals and mitigate impacts of high-stakes testing. Policy recommendations include reducing frequency of testing, development of alternative authentic assessments, and redesigning more robust measures of school-based accountability. Recommendations for practice include continued support for APs beyond initial certification, democratic leadership practices by APs, and more professional development that address issues of marginalization. Recommendations for future research include research to investigate relationships between schools with more students with disabilities and APs' social justice beliefs, and AP mentoring and rotational assignments. The study highlighted the complexity and ambiguity of the assistant principal position, the complicated, nuanced, and ongoing sensemaking of assistant principals, their importance at the forefront of campus leadership, and the impact these often-unnoticed school leaders have on their students, teachers, schools, and communities. [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.]